Humidification chamber for a respiratory assistance apparatus

ABSTRACT

A respiratory assistance apparatus includes a flow generator and a humidifier. The humidifier includes a humidification chamber. The humidification chamber comprises a water tub that is configured to receive a volume of water. A lid is hingedly coupled to the water tub for enclosing a volume contained within the water tub.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates to a humidification chamber for a respiratoryassistance apparatus that provides a stream of humidified gases to auser for therapeutic purposes. The respiratory assistance apparatus mayprovide respiratory assistance to patients or users who require a supplyof gases for respiratory therapies such as, but not limited to,humidification and/or flow therapy, Positive Airway Pressure (PAP)therapies, including but not limited to CPAP therapy, Bi-PAP therapy,and OPAP therapy, and which are typically used for the treatment ofdiseases such as Obstructive Sleep Apnea (OSA), snoring, or ChronicObstructive Pulmonary Disease (COPD).

Description of the Related Art

Respiratory assistance devices or systems for providing a flow ofhumidified and heated gases to a patient for therapeutic purposes arewell known in the art. Systems for providing therapy of this typetypically have a structure where gases are delivered to a humidifierchamber from a gases source, such as a blower (also known as acompressor, an assisted breathing unit, a fan unit, a flow generator ora pressure generator). As the gases pass over the hot water, or throughthe heated and humidified air in the humidifier chamber, they becomesaturated with water vapour. The heated and humidified gases are thendelivered to a user or patient downstream from the humidifier chamber,via a patient interface comprising a flexible gases conduit and a userinterface.

FIG. 1 shows a schematic view of one type of known respiratoryassistance system 1 for delivering humidified and heated gases to apatient. The system 1 comprises a housing 2 containing a blower unit 3and humidifier unit 4. In operation, atmospheric air 5 is drawn into theblower unit 3. The blower unit 3 generates a pressurized air or gasesstream which is delivered to the inlet 7 of a humidification chamber 8.The humidification chamber 8 comprises water and is heated by a heaterpad 9. The humidified and heated gases stream 10 exits thehumidification chamber via an outlet 11 of the humidification chamberand is delivered to the patient or user 12 via a flexible hose or gasesconduit 13 and user interface 14 as shown. The blower unit andhumidification unit are typically connected via a series of connectorsand/or conduits to allow gases to pass from the blower unit to thehumidifier unit.

The user interface 14 shown in FIG. 1 is a nasal mask, covering the noseof the user 12. However, it should be noted that in systems of thesetypes, a mask that covers the mouth and nose, a full face mask, a nasalcannula, or any other suitable user interface could be substituted forthe nasal mask shown. A mouth-only interface or oral mask could also beused. Also, the patient or user end of the conduit can be connected to atracheostomy fitting, or an endotracheal intubation.

The humidification chamber 8 typically comprises a rigid plasticreceptacle or container that can be filled with a volume of water. Inone known form, the base of the humidification chamber comprises acircular thermally conductive metal heater plate that is fixed within acomplementary aperture provided in the base of the humidificationchamber via overmolding of the plastic base about the peripheral edge ofthe heater plate. The overmolding forms a seal at the interface betweenthe perimeter edge of the heater plate and surrounding plastic basesurface of the chamber. In use, the heater plate contacts a heater pador heater base upon which the humidification chamber rests and heats thevolume of water in the chamber via conduction. Overmolding to couple theheater plate into the base of the plastic chamber can be a complicatedmanufacturing process and difficult to control.

In this specification where reference has been made to patentspecifications, other external documents, or other sources ofinformation, this is generally for the purpose of providing a contextfor discussing the features of the invention. Unless specifically statedotherwise, reference to such external documents is not to be construedas an admission that such documents, or such sources of information, inany jurisdiction, are prior art, or form part of the common generalknowledge in the art.

It is an object of the present invention to provide an improvedhumidification chamber, or to at least provide the public with a usefulchoice.

SUMMARY OF THE INVENTION

In a first aspect, the present invention broadly consists in ahumidification chamber for humidifying gases, comprising: a water tubthat is configured to receive a volume of water; a cradle defining anopen cavity within which the water tub is received; a lid hingedlycoupled to the cradle for enclosing the water tub to define the interiorvolume of the humidification chamber and which is movable between aclosed position in which the water tub is closed by the lid and an openposition in which the water tub is open; one or more operable clips forsecuring the lid in the closed position; a gases inlet for receiving aflow of gases into the interior volume of the humidification chamber;and a gases outlet through which a humidified flow of gases may exit theinterior volume of the humidification chamber.

In one form, the lid and cradle may be formed of rigid plastic. By wayof example, the lid and cradle may be hingedly coupled by a living hingeand are integrally formed as a single item.

In one form, the water tub may be formed of a thermally conductivematerial, such as but not limited to metal.

In one form, the water tub may be defined by a base surface and aperimeter wall that extends upwardly from the base, and wherein thecradle comprises a complementary base surface and upwardly extendingperimeter wall and wherein the perimeter wall of the cradle isdiscontinuous about the perimeter of the cradle so as to expose one ormore portions of the peripheral wall of the water tub retained withinthe cradle. In such forms, a heat transfer contact surface may protrudefrom the base surface of the water tub and the cradle may be providedwith a complementary aligned aperture through which the contact surfaceof the water tub extends such that it protrudes beyond the underside ofthe base surface of the cradle.

In one form, the water tub may be releasably received within the cradleby slidable engagement.

In one form, the gases inlet and gases outlet may be provided onopposite sides of the lid. In such forms, the lid may comprise avertical flow plane that extends downwardly from the underside of thelid in a central region of the lid.

In one form, the gases inlet may be coupled to an inlet conduit thatextends between an inlet end at the gases inlet and an outlet endlocated at or toward an upper central region of the interior volume ofthe humidification chamber and adjacent a first side surface of thevertical flow plane such that the incoming gases flow enters theinterior volume of the humidification chamber at that upper centralregion. Additionally, a flow director formation in the form of aninverted curved ramp surface may be located between the outlet end ofthe inlet conduit and the first side surface of the vertical flow plane.

In one form, the gases outlet may be coupled to an outlet conduit thatextends between an inlet end located at or toward an upper centralregion of the interior volume of the humidification chamber and adjacenta second side of the vertical flow plane and an outlet end at the gasesoutlet.

In one form, the lid may comprise one or more water fill apertures andat least one water fill aperture comprising an associated maximum waterlevel indicator comprising a tab member that is supported from theunderside of the lid such that it extends into the field of view of theinterior volume of the humidification chamber visible directly throughthe water fill aperture.

In one form, the humidification chamber may have an overall shapedefined by front and end walls between which side walls extend, and thewalls extending between an upper surface of the lid and base surface ofthe cradle, and wherein the lid is hingedly coupled to the cradle at therear end of the humidification chamber, and at least one operable clipis provided at the front end of the humidification chamber.

In one form, the chamber may comprise at least one operable clipprovided in the form of a torsion clip that is mounted to either the lidor cradle and which is configured to engage with a catch provided oneither the cradle or lid, respectively. By way of example, at least oneoperable clip may be provided that is hingedly coupled to the lid orcradle and which is configured to engage with a catch provided on eitherthe cradle or lid, respectively.

In a second aspect, the present invention broadly consists in ahumidification chamber for humidifying gases, comprising: a water tubthat is configured to receive a volume of water; a lid hingedly coupledto the water tub for enclosing the water tub to define the interiorvolume of the humidification chamber and which is movable between aclosed position in which the water tub is closed by the lid and an openposition in which the water tub is open; one or more operable clips forsecuring the lid in the closed position; a gases inlet for receiving aflow of gases into the interior volume of the humidification chamber;and a gases outlet through which a humidified flow of gases may exit theinterior volume of the humidification chamber.

In one form, the lid may be formed from rigid plastic. By way ofexample, the water tub may be formed of rigid plastic and may comprise abase surface and a perimeter wall that extends upwardly from the base,and wherein the base surface comprises a heater plate. In one form, theheater plate may be secured within an aperture of the base surface ofthe water tub by overmolding. In one arrangement, a peripheral couplingsurface of the heater plate may be secured within a peripheralengagement portion of the base surface about the aperture of the watertub by overmolding such that the thickness of the engagement portion isgreater than the thickness of remaining base surface. By way of example,the engagement portion may comprise an upper portion above the couplingsurface of the heater plate and a lower portion below the couplingsurface, and wherein the upper portion is at least as thick as theremaining base surface. By way of example, the heater plate may bemetallic.

In one form, the water tub may further comprise a step formation aboutthe inner surface perimeter of the wall of the water tub, the stepformation being configured at a height above the base surface of thewater tub corresponding to a maximum fill line indicator.

In one form, the base surface of the water tub may be domed such that itcurves outward toward a central apex defined by the heater plate.

In one form, the perimeter wall of the water tub may comprise one ormore reinforced regions. By way of example, the reinforced region(s) ofthe perimeter wall may comprise corrugated surfaces of alternatingridges and furrows.

In one form, the lid and water tub may be hingedly coupled by a livinghinge and are integrally formed as a single item.

In one form, the gases inlet and gases outlet may be provided onopposite sides of the lid. In such forms, the lid may comprise avertical flow plane that extends downwardly from the underside of thelid in a central region of the lid. In one arrangement, the verticalflow plane may further comprise a pair of side baffles that each extendfrom a respective side edge of the vertical flow plane toward the sideof the lid comprising the gases inlet.

In one form, the gases inlet may be coupled to an inlet conduit thatextends between an inlet end at the gases inlet and an outlet endlocated at or toward an upper central region of the interior volume ofthe humidification chamber and adjacent a first side surface of thevertical flow plane such that the incoming gases flow enters theinterior volume of the humidification chamber at that upper centralregion. Additionally, a flow director formation in the form of aninverted curved ramp surface may be located between the outlet end ofthe inlet conduit and the first side surface of the vertical flow plane.

In one form, the gases outlet may be coupled to an outlet conduit thatextends between an inlet end located at or toward an upper centralregion of the interior volume of the humidification chamber and adjacenta second side of the vertical flow plane and an outlet end at the gasesoutlet.

In one form, the gases outlet of the lid may comprise an engagementsurface about the perimeter of the gases outlet that is tilted outwardlysuch that an upper portion of the engagement surface is displacedfurther outward from the lid than a lower portion of the engagementsurface.

In one form, the lid may comprise one or more water fill apertures andat least one water fill aperture comprising an associated maximum waterlevel indicator comprising a tab member that is supported from theunderside of the lid such that it extends into the field of view of theinterior volume of the humidification chamber visible directly throughthe water fill aperture.

1. In one form, the humidification chamber may have an overall shapedefined by front and end walls between which side walls extend, and thewalls extending between an upper surface of the lid and base surface ofthe water tub, and wherein the lid is hingedly coupled to the water tubat the rear end of the humidification chamber, and at least one operableclip is provided at the front end of the humidification chamber.

In one form, the chamber may comprise at least one operable clipprovided in the form of a torsion clip that is mounted to either the lidor water tub and which is configured to engage with a catch provided oneither the water tub or lid, respectively. By way of example, at leastone operable clip may be provided that is hingedly coupled to the lid orwater tub and which is configured to engage with a catch provided oneither the water tub or lid, respectively.

In one form, the chamber may further comprise a seal about the perimeterof the chamber between the lid and water tub to seal the chamber when itis in a closed position.

In a third aspect, the present invention broadly consists in arespiratory assistance device configured to provide a heated andhumidified gases stream, comprising: a device gases inlet configured toreceive a supply of gases; a blower configured to generate a pressurisedgases stream from the supply of gases; a humidifier configured to heatand humidify the pressurised gases stream; a device gases outlet for theheated and humidified gases stream; and a flow path for the gases streamthrough the respiratory device from the gases inlet though the blowerunit and humidification unit to the gases outlet, and wherein thehumidifier comprises a sealable humidification compartment that isconfigured to receive and retain a removable humidification chamberaccording to either of the first or second aspects of the invention.

In one form, the humidification compartment may comprise a lid that ismovable between an open position to enable removal of the humidificationchamber and a closed position to seal the humidification chamber withinthe humidification compartment.

In one form, the humidification compartment may comprise a gases inletconnected to the flow path to receive the pressurised gases stream fromthe blower to create a pressurised humidification compartment and agases outlet connected to the device gases outlet of the flow path.

In one form, the gases inlet of the humidification chamber may be openwithin the humidification compartment to receive an incoming flow ofgases from within the pressurised humidification compartment.

In one form, the gases outlet of the humidification compartment may besealingly connected to the gases outlet of the humidification chamber.

In one form, the humidification compartment may comprise a heater padupon which the humidification chamber sits.

In one form, the device may be contained within a single housing.

In one form, the device may be a CPAP respiratory device.

The humidification chamber of the third aspect of the invention may haveany one or more of the features mentioned in respect of either of thefirst and second aspects of the invention.

The term “comprising” as used in this specification and claims means“consisting at least in part of”. When interpreting each statement inthis specification and claims that includes the term “comprising”,features other than that or those prefaced by the term may also bepresent. Related terms such as “comprise” and “comprises” are to beinterpreted in the same manner.

It is intended that reference to a range of numbers disclosed herein(for example, 1 to 10) also incorporates reference to all rationalnumbers within that range (for example, 1, 1.1, 2, 3, 3.9, 4, 5, 6, 6.5,7, 8, 9 and 10) and also any range of rational numbers within that range(for example, 2 to 8, 1.5 to 5.5 and 3.1 to 4.7) and, therefore, allsub-ranges of all ranges expressly disclosed herein are hereby expresslydisclosed. These are only examples of what is specifically intended andall possible combinations of numerical values between the lowest valueand the highest value enumerated are to be considered to be expresslystated in this application in a similar manner.

As used herein the term “and/or” means “and” or “or”, or both.

As used herein “(s)” following a noun means the plural and/or singularforms of the noun.

The invention consists in the foregoing and also envisages constructionsof which the following gives examples only.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will be described by way ofexample only and with reference to the drawings, in which:

FIG. 1 shows a schematic view of a known form of respiratory assistanceapparatus in which the blower unit and humidifier unit are integratedinto a single main housing;

FIG. 2 shows a schematic view of the main components and configurationof a respiratory assistance apparatus which may utilise a humidificationchamber of the invention;

FIG. 3 shows a lower perspective view of a closed humidification chamberin accordance with a first embodiment of the invention comprising a lid,discontinuous cradle and water tub;

FIG. 4 shows a plan view of the humidification chamber of FIG. 3;

FIG. 5 shows an underside view of the humidification chamber of FIG. 3;

FIG. 6 shows a side elevation view of the gases inlet side of thehumidification chamber of FIG. 3;

FIG. 7 shows a side elevation view of the gases outlet side of thehumidification chamber of FIG. 3;

FIG. 8 shows an elevation view of the rear end of the humidificationchamber of FIG. 3;

FIG. 9 shows an elevation view of the front end of the humidificationchamber of FIG. 3;

FIG. 10 is a perspective cross-sectional view of the closedhumidification chamber through line AA of FIG. 6;

FIGS. 11A, 11B and 11C show upper perspective, side elevation, and lowerperspective views of the water tub of the humidification chamber of FIG.3;

FIG. 12 shows an underside view of the closed humidification chamber ofFIG. 3 but with the water tub omitted from view;

FIG. 13 shows one perspective view of the cradle and lid of thehumidification chamber of FIG. 3 in an open position;

FIG. 14 shows another perspective view of the cradle and lid of thehumidification chamber of FIG. 3 in an open position;

FIG. 15 shows a plan view of the cradle and lid of the humidificationchamber of FIG. 3 in an open position;

FIG. 16 shows a side elevation view of the cradle and lid of thehumidification chamber of FIG. 3 in an open position;

FIG. 17 shows a close-up perspective view of upper side of the lid ofthe humidification chamber of FIG. 3;

FIG. 18 shows a close-up perspective view of the underside of the lid ofthe humidification chamber of FIG. 3;

FIG. 19 shows another close-up perspective view of the underside of thelid of the humidification chamber of FIG. 3;

FIG. 20 shows a cross-sectional view of the closed humidificationchamber through line CC of FIG. 4;

FIG. 21A shows a perspective view of the first embodiment humidificationchamber but with a first alternative form of clipping mechanism and withthe humidification chamber closed;

FIG. 21B shows the humidification chamber of FIG. 21A in an openposition and with the water tub removed;

FIG. 21C shows a close-up perspective view of the rear end of the cradleof the humidification chamber of FIG. 21A and the catch formation of theclipping mechanism;

FIG. 22A shows the lid of the first embodiment humidification chamberwith a second alternative type form of clipping mechanism;

FIG. 22B shows the cradle and lid of the first embodiment humidificationchamber with a third alternative type form of clipping mechanism;

FIG. 23A shows a perspective view of the first embodiment humidificationchamber but with a fourth alternative form of clipping mechanism andwith the humidification chamber closed;

FIG. 23B shows a side elevation view of the humidification chamber ofFIG. 23A;

FIG. 24A shows a cross-sectional view of the first embodimenthumidification chamber with an first alternative water level indicatorin the form of a variant of the tab water level indicator;

FIG. 24B shows a plan view through the water fill aperture of the lid ofthe humidification chamber of FIG. 24A and showing the alternative formof tab water level indicator;

FIG. 25 shows a cross-sectional view of the first embodimenthumidification chamber with a second alternative type of water levelindicator in the form of a conical water level indicator;

FIG. 26 shows a plan view of the lid of the humidification chamber ofFIG. 25 and showing the user's view of the conical water levelindicator;

FIG. 27A shows a perspective view of a closed humidification chamber inaccordance with a second embodiment of the invention comprising a lid,full cradle and water tub;

FIG. 27B shows the lid and cradle of the second embodimenthumidification chamber lid and full cradle in an open position withwater tub omitted;

FIG. 27C shows a perspective view of the front end of the full cradleand the catch of the clipping mechanism of the second embodimenthumidification chamber;

FIG. 28A shows a first upper perspective view of a humidificationchamber, in a closed position, in accordance with a third embodiment ofthe invention comprising a lid and water tub with an overmolded heaterplate, and which shows the rear end and gases inlet side of thehumidifier chamber;

FIG. 28B shows a second upper perspective view of the third embodimenthumidification chamber of FIG. 28A, and showing the front end and gasesoutlet side of the humidification chamber;

FIG. 28C shows a plan view of the third embodiment humidificationchamber of FIG. 28A;

FIG. 28D shows an underside view of the third embodiment humidificationchamber of FIG. 28A;

FIG. 28E shows a side elevation view of the gases inlet side of thethird embodiment humidification chamber of FIG. 28A;

FIG. 28F shows a side elevation view of the gases outlet side of thethird embodiment humidification chamber of FIG. 28A;

FIG. 28G shows an elevation view of the rear end of the third embodimenthumidification chamber of FIG. 28A;

FIG. 28H shows an elevation view of the front end of the thirdembodiment humidification chamber of FIG. 28A;

FIG. 28I shows a cross-sectional view of the third embodimenthumidification chamber through line EE of FIG. 28C;

FIG. 28J shows a close-up view of area FF of FIG. 28I;

FIG. 28K shows a similar elevation view of the front end of the thirdembodiment humidification chamber as FIG. 28H but at an angle whichshows the angled profile of the gases outlet;

FIG. 28L shows an upper perspective view of the third embodimenthumidification chamber in an open position;

FIG. 28M shows a lower perspective view of the third embodimenthumidification chamber in an open position;

FIG. 28N shows another perspective view of the third embodimenthumidification chamber in an open position from the gases inlet side ofthe humidification chamber;

FIG. 28O shows a first upper perspective view of a lower part of ahumidification compartment for receiving the third embodimenthumidification chamber, with the gases inlet of the compartment beingvisible;

FIG. 28P shows a second upper perspective view of the humidificationcompartment part of FIG. 28O, with the gases outlet of the compartmentbeing visible;

FIG. 28Q shows a plan view of the third embodiment humidificationchamber installed in the humidification compartment part of FIG. 28O;

FIG. 28R shows a side perspective view of the third embodimenthumidification chamber installed in the humidification compartment partof FIG. 28O;

FIG. 28S shows a cross-sectional view of the third embodimenthumidification chamber installed in the humidification compartment partthrough line GG of FIG. 28Q;

FIG. 28T shows a cross-sectional view of the third embodimenthumidification chamber installed in the humidification compartment partthrough line HH of FIG. 28Q;

FIG. 29A shows a perspective view of a fourth embodiment humidificationchamber comprising a lid, sleeve and water tub;

FIG. 29B shows a cross-sectional view through the fourth embodimenthumidification chamber;

FIG. 30A shows a perspective view of a lid of a humidification chamberin accordance with a fifth embodiment of the invention comprising a lidwhich clips into a water tub;

FIG. 30B shows a perspective view of the water tub of the fifthembodiment humidification chamber;

FIG. 30C shows a perspective view of the lid and water tub of the fifthembodiment humidification chamber in an assembled and closedconfiguration;

FIG. 31A shows an upper perspective view of a closed humidificationchamber in accordance with a sixth embodiment of the inventioncomprising a ducted lid which clips into a water tub;

FIG. 31B shows a lower perspective view of the sixth embodimenthumidification chamber;

FIG. 32 shows a perspective view of the water tub of the sixthembodiment humidification chamber;

FIG. 33 shows a first underside perspective view of the ducted lid ofthe sixth embodiment humidification chamber;

FIG. 34 shows a side elevation view of the ducted lid of FIG. 33;

FIG. 35 shows a second underside perspective view of the ducted lid ofFIG. 33; and

FIG. 36 shows a close-up cross-sectional view of a rear end of avariation of the first embodiment humidification chamber of FIG. 3 thathas a seal between the lid and water tub.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Overview

The invention relates to a humidification chamber for a respiratoryassistance apparatus (respiratory device) that supplies a flow or streamof heated and humidified respiratory gases to a user or patient forrespiratory therapies, such as, but not limited to, CPAP therapy.

For context, FIG. 2 shows an example of a typical schematicconfiguration of a respiratory device 20 within which the humidificationchamber of the invention may be employed, although this is not intendedto be limiting to the uses of the humidification chamber. Therespiratory device 20 comprises a humidification unit or humidificationcompartment 22 that receives and retains a removable humidificationchamber 24 in use. In this embodiment, the humidification compartment 22may be formed within the housing of the respiratory device and may be anopenable compartment having a lid so the humidification chamber 24within the humidification compartment 22 may be accessed for removal forcleaning or filling. Typically the humidification compartment 22 issealed and/or pressurised when the lid is closed. The humidificationchamber 24 is filled with a volume of water as indicated at 26 and thechamber 24 rests upon a heater pad or heater base 28. As is known in theart, the heater pad 28 is powered to heat the water 26 in thehumidification chamber 24 during use via heat transfer through the baseof the humidification chamber 24 of which at least a portion isthermally conductive.

The respiratory device 20 comprises a blower 30 which draws atmosphericair or other therapeutic gases through an inlet 32 and generates apressurised gases stream 34 at an outlet of the blower. The outlet ofthe blower 30 is fluidly connected to an inlet 36 of the humidificationcompartment 22 via connecting conduits 38 extending to the inlet 36 ofhumidification compartment 22. As the humidification compartment issealed when closed, the gases stream 34 entering the inlet 36pressurises the compartment and gases flow into the open gases inlet 37of the humidification chamber 24. It will be appreciated that inalternative embodiments, the inlets 36,37 of the compartment 22 andchamber 24 may be sealingly connected by a connector or other sealingconfiguration.

The pressurized gases stream passes through the humidification chamber24 and exits via gases outlet 40 of the humidification chamber. In thisembodiment, the gases outlet 40 of the chamber 24 is sealingly connectedto or sealingly engaged with an outlet 41 of the humidificationcompartment 22 as shown. It will be appreciated that in alternativeembodiments, the outlets 40, 41 of the compartment 22 and chamber 24need not be sealingly connected by a connector or otherwise sealinglyengaged. In the embodiment shown, the outlet 41 of the humidificationcompartment 22 is fluidly connected via connectors and/or conduits to apatient interface for delivery to a patient 42. The patient interfacetypically comprises a flexible gases conduit 44 coupled at one end tothe main gases outlet of the respiratory device 20 and to a userinterface 46 at the other end.

In the following embodiments, the humidification chamber 24 is typicallyreceived and retained within a complimentary enclosed and sealablehumidification compartment 22 formed in the housing of the respiratorydevice 20. However, it will be appreciated that the humidificationchamber 24 could alternatively be received and retained in an open orexposed compartment or on a support platform comprising the heater pad28 in alternative embodiments with the gases inlet of the chamber beingconnected to the blower outlet by conduits and/or connectors and thegases outlet of the chamber being connected by conduits and/orconnectors directly or indirectly to the patient interface.

First Embodiment Humidification Chamber—Discontinuous Cradle with Lid

Referring to FIGS. 3-20 a first embodiment of the humidification chamber50 will be explained in further detail. As explained above, thehumidification chamber 50 is configured to be received and retain withina complimentary humidification compartment (not shown) provided withinthe housing of the respiratory device. Typically the compartmentcomprises a heater base or heater pad upon which the humidificationchamber sits. The humidification compartment is accessible via anopenable lid to enable the humidification chamber 50 to be inserted andremoved as required, for example for cleaning and/or refilling.

As shown in FIG. 3, the humidification chamber or chamber assembly 50comprises a cradle or lower part generally indicated at 52 that isshaped to receive and retain a complimentary sized and dimensioned watertub or container 54. An upper part or lid 56 is hingedly coupled to thecradle 52 and is moveable between a closed position (shown in FIG. 3) inwhich the lid securely retains the water tub 54 within the cradle 52 andan open position (see FIG. 14 for example) in which the lid is pivotedaway from the cradle 52 to enable the water tub 54 to be removed fromthe cradle for cleaning, refilling or replacement for example. As willbe explained later, the lid may comprise baffling in the form of aconfiguration of conduits and/or flow planes and guides to control theflow path of the gases stream through the chamber between the inlet andoutlet.

In this embodiment, the cradle 52 and lid 56 are formed of a rigidplastic by injection moulding or the like. Typically, the cradle 52, lid56 and hinged coupling between the two components are integrally formedtogether as a single item, although in alternative embodiments the lidand cradle may be formed as separate parts and then hingedly coupled viaone or more hinges. The lid and/or cradle may be substantiallytransparent or formed as opaque depending on design requirements. Thewater tub or chamber base 54 is formed of a rigid and thermallyconductive material, typically pressed or shaped from sheet metal, suchas aluminium, stainless steel or any other suitable material, or couldbe formed by die casting for example.

It will be appreciated that in alternative embodiments, the cradle 52,lid 56 and water tub 54 could be formed from other materials or in otherways. For example, the cradle 52 and lid 56 could be formed by vacuumforming. The cradle and/or lid could also be formed from metal, whetherpressed from sheet metal or formed from die casting for example. Thewater tub could alternatively be formed from a heat conductive plasticin alternative embodiments.

Shape of the Humidification Chamber

In this embodiment, the overall shape of the humidification 50 issubstantially rectangular as shown in the plan view of FIG. 4. Thehumidification chamber 50 is defined by first 58 and second 60 endbetween which first 62 and second 64 sides extend. In this explanation,the first end 58 is considered the rear end and the second end 60 isconsidered the front end of the humidification chamber. The first side62 may be considered the inlet side of the humidification chamber as itcontains the inlet through which the pressurized gases stream from theblower enters the humidification chamber. The second side 64 may beconsidered the outlet side of the humidification chamber as it containsthe outlet for the humidified gases stream which exits thehumidification chamber. It will be appreciated that in an alternativedescription of the chamber, the ends could be considered the sides andvice versa, depending on the context.

In this embodiment, the corners joining the ends 58,60 and sides 62,64are curved or rounded as generally indicated at 66, although this is notessential and the corners may be right-angle corners or any otherprofiled shape. In this embodiment, the corner 66 a joining the frontend 60 and inlet side 62 is larger than the remaining corners, althoughthis is not essential. It will be appreciated that in alternativeembodiments the humidification chamber assembly may be formed in anydesired shape or profile, including circular or otherwise and that thesame principals of construction and configuration will generally apply.

Cradle

The cradle 52 is configured to receive and retain the water tub 54 whichhas a complimentary shape and slightly smaller dimensions so that it canslide down into the open cavity formed by the cradle. The tightness ofthe fit between the water tub 54 and cradle 52 may be varied. In someembodiments it may be snug with a friction fit and in other embodimentsit may be a loose fit such that the water tub may easily slide into andout of the cradle preferably without any or minimal force or pressureapplied by the user to assemble or release the parts. When the chamberis closed, the cradle acts to hold the water tub securely and accuratelyup against the lid. In particular, the cradle typically holds the watertub up to the lid around the full mouth of the chamber toprevent/minimise splash over of water between the lid and water tub. Thecradle also has the dual function of holding the water tub in placewhile also hinging the lid, and keeps the lid and water tub aligned sothat when the user goes to close the chamber they do not have to alignthe lid and water tub.

Referring to FIG. 13, in this embodiment, the cradle 52 comprises a baseor bottom surface 70 upon which the base or bottom surface of the watertub 54 rests. The base 70 of the cradle 52 also comprises a centralaperture 72 which enables the heater base or heater pad of therespiratory device to contact a portion of the base of the water tub 54for heat transfer to heat up the water volume in the water tub 54 aswill be explained in further detail later. The cradle 52 has adiscontinuous perimeter wall, which in this embodiment is in the form ofat least one pair of opposed walls that extend upwardly from theperimeter of the base 70 to form a cradle-like structure with an openreceiving cavity. In this embodiment, the cradle 52 comprises front 54and rear 76 walls that extend upwardly from the base 70. The end wallformations 74, 76 extend along each respective front and rear end of thecradle and extend about at least portion of the corner perimeter of thecradle 52 such that each end wall formation comprises a central planarportion which extends into curved corner portions identified at 74 a, 74b and 76 a, 76 b at each respective end of the central planar portion.

In this embodiment, the end wall formations 74, 76 each extend about theentire corner region of the cradle and terminate along respective sidesof the cradle prior to meeting each other to thereby provide open sidewall formations in the cradle which expose the water tub 54 whenretained in the cradle 52. For example, FIG. 6 shows the inlet side ofthe cradle 52 with the front 74 and rear 76 end walls extending aboutthe respective corners 74 a,76 a of the cradle and along the side of thecradle, and each terminated at a sloped curved edge 74 c,76 c extendingdownwardly from the upper edge of the cradle to the base 70. It will beappreciated that the terminating edges 74 c, 76 c need not necessarilybe declining at an angle with a curving profile but maybe abruptvertical edges in alternative forms of the cradle if desired. Likewise,a similar configuration is provided on the opposite outlet side of thecradle shown in FIG. 7. On the outlet side, the end walls 74 and 76 alsoextend about respective corners 74 b, 76 b and terminate at slopedcurved edges 74 d, 76 d which extend from the upper edge of the cradledown to the base.

The cradle 52 substantially encapsulates the water tub 54 about at leastthe opposing end walls of the water tub and additionally corner portionsof the water tub 54. As shown in FIGS. 6 and 7, in this embodiment theperimeter wall of the cradle is discontinuous such that the walls of thecradle do not encircle or surround the entire perimeter walls of thewater tub 54 completely or continuously, thereby leaving a portion orportions of the water tub wall exposed (not covered by the cradle). Inthis embodiment, the cradle walls are discontinuous on each side of thecradle such that the majority of the side walls of the water tub 54 areexposed (i.e. not covered by the cradle walls). For example, in thisembodiment the opposed end walls 74 and 76 terminate at edges on thesides of the cradle at or towards their respective ends. It will beappreciated that displacement or distance between the terminating edgesof the end walls 74 and 76 on each side may be varied to expose more orless of the water tub side wall portion as desired. For example, eitheror both of the end walls may terminate at or toward the center of thewall or more toward the corner portion of the walls.

In use, the cradle provides a thermally insulated barrier or surfacewhich the user may grasp or hold the humidification chamber by afterremoving the chamber from the respiratory device for refilling orcleaning for example. This enables the user to avoid direct contact withthe heated thermally conductive water tub, and thereby avoid potentialburns or discomfort. Additionally, the removability of the water tubfrom the cradle allows for both parts to be cleaned thoroughly.

Water Tub

Referring to FIGS. 11A-11C, the water tub 54 is shown in isolation. Aspreviously mentioned, water tub 54 is typically formed from sheet metalor similar and operates as a receptacle or container for holding avolume of liquid, such as water. As shown, the water tub 54 has a shapethat is complimentary to the cradle such that the water tub 54 may besnugly received into the cradle 52, for example via slidable engagementwith a friction fit.

In this embodiment, the water tub 54 is substantially rectangular with abase or base surface 80 from which upwardly extending perimeter wallsextend. In particular the water tub 54 comprises front 82 and rear 84walls and first 86 and second 88 side walls extending between the endwalls. The corner wall portions 90 joining the end and side walls arepreferably curved or round with a similar curvature or radius thatcompliments the overall cradle plan view shape explained with referenceto FIG. 4 previously. As shown, one of the corners 90 a is larger inradius than the remaining corners to complement the larger corner 66 aof the cradle. This configuration allows the water tub to be received inthe cradle in a single orientation only to assist the user whenassembling the parts together such that the inlets and outlets of thechamber and humidification compartment are correctly aligned with eachother. It will be appreciated that the water tub, cradle and lid mayhave any other profiled corners, including 90° right-angle corners andthe profiled corners may be uniformed or non-uniformed from corner tocorner.

Referring to FIG. 11B the upper edge of the perimeter walls is providedwith a continuous outwardly extending lip, flange or rim 92. In thisembodiment, the lip 92 extends substantially horizontally ortransversely outward from the vertical perimeter wall at the upper edgeof the perimeter wall. The perimeter lip 92 is optional. When provided,it is configured to engage, abut or rest upon the upper edges 74 e, 76 e(see FIGS. 13 and 14) of the end walls 74 and 76 of the cradle 52 andwhich is more readily visible in the cross-sectional view of FIG. 10,for example.

The water tub 54 is provided with a heat transfer contact surface orportion 94 that protrudes from the underside of the base surface 80. Thecontact surface 94 is preferably integrally formed with the remainder ofthe water tub. For example, the contact surface 94 may be pressed outfrom the base surface 80. In this embodiment, the contact surface 94 iscircular and of a diameter substantially complimentary to the centralaperture 72 provided in the base surface 70 of the cradle 52 (see FIG.13). In particular, the contact surface 94 of the water tub 54 issubstantially aligned with the complimentary aperture 72 of the cradle52 and is of a depth relative to remainder of the base surface 80 thatenables it to extend through aperture 72 so as to protrude below theunderside of base surface 70 of the cradle as shown in FIG. 6. When thehumidification chamber 50 is inserted into a complimentaryhumidification compartment in the respiratory device, the protrudingcontact surface 94 of the water tub 54 rests upon or abuts a heater baseor pad within the compartment, which may be of a complimentary size andshape, although this is not essential. The heat from the heater base isthen transferred through the thermally conductive (e.g. metal) contactsurface 94 to the volume of water within the water tub via conduction aswill be appreciated.

In alternative embodiments, the contact surface need not necessarilyprotrude beyond the remainder of base surface 80 of the water tub. Forexample, in one alternative embodiment, the base surface 80 may beplanar with a flush contact surface 94 and the heater base or pad may beshaped in such that it protrudes through the aperture 72 of the cradlefor engagement or contact with the base surface 80 of the water tub 54.In a further alternative embodiment, the contact surface 94 may berecessed relative to the remaining underside of the base surface 80 ofthe water tub, i.e. such that it protrudes upwardly into the water tub.With such an embodiment, again the complimentary heater base or pad maybe configured with a height and shape that enables it to protrudethrough aperture 72 in the cradle for engagement into the recess orcavity created by the recessed contact surface in the base of the watertub 54.

In the above embodiments, the contact surface and related componentry isdescribed for a circular contact surface and heater pad, although itwill be appreciated that any other alternative shape of contact surfacemay be employed, including square, rectangular or any other suitableshape.

Lid

Referring to FIGS. 3 and 4 the lid 56 of the humidification chamber 50has a shape when viewed in plan (see FIG. 4) substantially correspondsto the shape of the cradle 52 and water tub 54. In this embodiment, thelid comprises a main body portion 100 which forms upper surface or topof the humidification chamber and has a substantially rectangularoverall shape with rounded corners which corresponds to the outer shapeof cradle 52 and water tub 54. Extending downwardly from the mainportion 100 are perimeter walls. For example, front 102 and rear 104 endwalls are provided at each end of the main portion as can be seen mostclearly in FIG. 18. Additionally, first 106 and second 108 side wallsextend along the sides of the main body portion 100 between the frontand rear end walls 102, 104. The first side wall 106 is on the inletside of the humidification chamber and the second side wall 108 is onthe outlet side of the humidification chamber. Rounded corner wallportions 110 are also provided which join the side and end walls to forman overall perimeter wall extending vertically downwardly from thesubstantially horizontally extending main body portion 100.

In this embodiment, a perimeter ledge or flange 105 (see FIGS. 10 and18) is provided about the entire perimeter of the lid. The ledge 105extends outwardly from perimeter walls and in a substantially horizontaldirection in this embodiment, although an angled ledge may be used as analternative. The ledge is provided towards but displaced from the loweredge 107 of the perimeter vertical walls of the lid 56. In use, thelower surface of the ledge 105 of the lid is configured to abut orengage with the upper surface of the rim 92 of the water tub 54. In thisembodiment, the outer surface of the lower perimeter wall portion 91 ofthe lid 56 below the ledge 105 has some clearance (i.e. is displaced bya small amount) from the adjacent inner surface of the upper perimeterwall portion 93 of the water tub below the rim 92 as shown in FIG. 10.This allows the lid to engage and disengage with the water tub withoutthe user being required to apply significant force. In this embodiment,the lower perimeter wall portion 91 of the lid acts as a water guard orshield in that it deflects water from splashing out between the lid andwater tub, and additionally assists in aligning the lid into engagementwith the water tub when a user is closing the chamber. It will beappreciated that other embodiments may be configured for a tighterfriction fit such that the lower perimeter wall portion 91 of the lidabuts or contacts the upper perimeter wall portion 93 of the water tub.

Water Fill Holes

Referring to FIGS. 3 and 4, the lid 56 is provided with one or morewater fill apertures or holes through which water may be poured to fillor refill the water tub 54 of the humidification chamber. In thisembodiment, two identical water fill holes generally indicated at 120are provided, one at or toward front end of the lid and the other at ortoward the rear end of the lid, although the location of the water fillholes may be varied from this configuration. In this embodiment, eachwater fill hole is provided by a funnel-like formation which extendsinto the humidification chamber from the main body portion 100 of thelid. For example, each water fill hole 120 is provided with afrusto-conical formation 122 having a first end flush with the main bodyportion 100 of the lid and extending down into the humidificationchamber with a progressively reducing diameter to terminate at a secondend corresponding to the water fill aperture edge 124, which in thiscase is circular. It will be appreciate that the funnel-like formationof the water fill holes is optional, but helps reduce splashing orspillage during filling of the chamber. In an alternative embodiment,the water fill holes may simply be apertures formed in the main bodyportion, circular or otherwise, without any such guiding funnel-likeformation.

In this embodiment, each water fill hole 120 is provided with one ormore concentric circular raised sealing ribs 121 or protrusionsextending about the perimeter of the water fill hole. These sealing ribs121 may be integrally formed with the lid or attached to the lid. Thesealing ribs 121 may be formed of a rigid or hard plastic such that asoft seals may sealingly engage with the ribs to close the water fillholes. By way of example, the soft seals may be provided on the lid ofthe humidification compartment within which the chamber is located inuse. In an alternative embodiment, the ribs 121 may be a soft overmoldedplastic or rubber or silicone for sealingly engaging with a hard surfaceor formations provided on the lid of the humidification compartment toclose the water fill holes when in use within the respiratory device.

Water Level Indicators

Referring to FIG. 18, the humidification chamber 50 comprises at leastone water level indicator which is configured to provide the user withat least an indication as to when the water level is approaching amaximum water level. In this embodiment, a water level indicator 130 isprovided for each water fill aperture 120 and is in the form of a tabwater level indicator 130 comprising a tab or member that is supportedfrom the lid and which extends down into the interior volume of thehumidification chamber, and in particular into the region defined by thewater tub 54. In this embodiment, each water level indicator 130comprises a substantially vertically extending support member 132 whichextends downwardly from the underside of the edge 124 of the water fillaperture and terminates with an inwardly extending tab portion or member134 that extends into the substantially vertical pouring channel regionor viewing zone associated with the water fill aperture. In particular,the tab portion 134 is substantially visible when a user looks directlyinto the centre of the water fill aperture from above, i.e. it islocated in the field of view into the interior of the chamber from thewater fill aperture. In this embodiment, the angle between the verticalsupport member 132 and tab portion 134 is obtuse such that tab portion134 extends with a downward slope from vertically extending supportmember 132. As shown in FIGS. 4 and 18, each tab portion 130 is providedwith a maximum water level indication formation 138. In this embodiment,the maximum water level indicator formations 138 are provided astriangular formations extending outwardly from either side of the tabportion 134, although it will be appreciated that any other form ofindicators could be utilised, including printed indicators, markings orindicia, such as printed lines, or otherwise. As the tab portion 134 hasa downward slope or tilt relative to the horizontal, the user isprovided with warning that they are approaching the maximum water levelas they are filling the water tub and as the water level begins to riseinto contact with the tab portion 134. However, it will be appreciatedthat in alternative embodiments, the tab portion 134 may besubstantially horizontal such that there is a 90° or right angle betweenthe vertical support member 132, and in such embodiments the user isalerted to filling the water tub to the maximum level as soon as thewater contacts the tab. It will be appreciated that the larger thedownward slope or tilt on the tab portion 134, the more warning isprovided to the user that they are approaching the maximum water levelfill volume as they see the water level on the tab progressivelyapproaching the maximum water level indication formation 138.

By way of further explanation, the viewing zone associated with waterfill apertures 120 is the visible region into the interior of thechamber that is viewable when the user is located directly above thecentre of the water fill aperture. For example, with reference to FIG.20, the viewing zone can be considered as a virtual cylindrical zoneextending downwardly from the edge 124 of the water fill aperture 120 asrepresented between the arrows BB in the cross-sectional view of FIG. 20of the humidification chamber. As shown, the tab portion 134 containingthe maximum fill level indicator formation 138 is configured to extendinto the viewing zone of the water fill aperture 120. This means thewater level indicator is directly viewable through the water fillaperture and can be seen by the user simultaneously while fillingthrough the same aperture.

Lid Inlet

The lid 56 is provided with a gases inlet through which a pressurizedgases stream generated by the blower of the respiratory device may flowthrough into the interior of the humidification chamber 50. Referring toFIGS. 3-6, the gases inlet 140 is provided on the inlet side 62 of thehumidification chamber 50. As shown in FIG. 6 the gases inlet 140 isprovided in a form of an aperture, in this case rectangular but could beany other shape such as circular or otherwise, provided through theinlet side perimeter wall 106 of the lid 56. In this embodiment, thegases inlet 140 is centrally located along the perimeter wall 106,although this position may be varied. Referring to FIG. 18, in thisembodiment the inlet aperture 140 is provided with an associated inletchannel or conduit 142 that channels or directs the inlet gases flowstream into a central zone or region of the lid before exiting theconduit 142 into the interior of the humidification chamber. In thisembodiment, the inlet conduit 142 extends between a first end 142 alocated at the inlet aperture of the wall 106 and terminates at a secondend 142 b located toward a central zone of the lid. The hollow inletconduit 142 has a cross-sectional shape that corresponds to the shape ofthe inlet aperture 140 and extends inwardly in a substantiallyhorizontal direction from the vertical perimeter wall 106 of the lid 52.The inlet conduit 142 extends into a central zone of the lid to assistin minimizing or reducing water backflow into the blower and device ifthe respiratory device is accidently tilted or tipped over from itsnormal upright operating orientation.

In this embodiment, the gases inlet 140 and inlet conduit 142 is locatedat or toward the top of the lid. However, in alternative embodiments,the lid may be deeper with taller perimeter walls, and the inlet 140 andconduit 142 may be displaced away from the top of the lid, for examplelocated at or toward the bottom of the lid. Such a configurationprovides a volume of space above the inlet in the lid for water tocollect during tilting of the chamber, and may reduce the likelihood ofwater backflow through the inlet.

At the exit of the inlet conduit 142, a flow directing formation 144 isprovided for directing the gases stream exiting the inlet conduit. Inthis embodiment, the flow direction formation 144 is in the form of acurved inverted ramp surface that begins at or towards the main bodyportion 100 of the lid at the exit end 142 b of the inlet conduit 142and terminates at a first side 146 b of a vertical flow panel 146 whichextends downwardly from the main body portion 100 of the lid. Thisconfiguration causes some of the incoming gases stream to turn back uponitself back toward the inlet walls of the humidification chamber whereit is humidified before circulating back around past the side edges 146e of the flow panel 146 toward the outlet of the humidification chamber.The configuration also assists in directing the air flow directly intothe surface of the water to increase the absorption of moisture from thewater into the incoming gases. The vertical flow plane 146 is displacedfrom the exit end 142 b of the inlet conduit 142.

FIG. 20 shows the first side 146 b of the vertical flow panel 146. Inthis embodiment, the width (W) of the vertical flow panel 146 or baffleis shorter than the overall length of the humidification chamber fromthe front end 60 to the rear end 58 but preferably wider than the width(W1) of the inlet conduit 142. In this embodiment, the height (H) of thevertical flow panel is such that it's lower edge 146 a at least extendsbelow the lower edge 142 a of the inlet conduit 142 and typicallyextends further at least below the horizontal maximum water level line,indicated by the indicator formations 138 of the tab water levelindicators. In this embodiment, the lower edge 146 a of the verticalflow plane 146 a is situated between the maximum water level indicatorformation 138 and the lower base surface 80 of the water tub 54, but mayin an alternative embodiment extend substantially to the bottom surface80 of the water tub 54. Preferably, the height of the vertical flowpanel 146 is such that its lower edge 146 a extends into or through thesurface of the volume of water in the water tub 54, for at least watervolumes that reach the maximum water level line, and more preferably thelower edge 146 a is configured to extend into the surface of the waterfor at least a portion of water volumes below the maximum water levelline, and even more preferably all water volumes (i.e. where the loweredge 146 a extends substantially to the base surface of the water tub).Typically, the height of the flow panel is configured such that itprotrudes or penetrates sufficiently deeply into the surface of thewater to prevent gases exiting the inlet conduit 142 from passingunderneath the lower edge 146 a and directly to the outlet conduit 152,such that the gases are forced to flow around the flow panel andincreasing the path the gases take around the chamber while exposed tothe water vapour before exiting the chamber. If the height of the flowpanel is too short such that gases can travel under the flow paneldirectly to the outlet, then this results in a shortened flow path andreduced humidification, and can also result in the gases stream blowingor splashing water into the outlet conduit 152 as the gases streamtravels back up from underneath the flow panel.

Lid Outlet

Referring to FIGS. 4 and 7, a gases outlet 150 is provided on theopposite side of the humidification chamber to the gases inlet 140. Inthis embodiment, the gases outlet 150 is provided on the outlet sideperimeter wall 108 of the lid 56 of the humidification chamber and likethe gases inlet 140 is centrally located relative to the front and rearends of the humidification chamber, although this is not essential. Thegases outlet 150 comprises an aperture extending through the perimeterwall 108 that is substantially rectangular, although other shapedapertures such as circular or otherwise could alternatively be utilized.Once the gases are heated and humidified in the humidification chamber,the gases stream exits the humidification chamber via gases outlet 150.

Referring to FIGS. 12 and 19, in this embodiment the gases outlet 150comprises an outlet conduit 152 that extends into a central zone orregion of the lid of the humidification chamber from gases outletaperture in a horizontal or perpendicular direction relative to theperimeter wall 108. In particular, the outlet conduit 152 extends from afirst end 152 a located at the aperture of the gas outlet 150 in thewall 108 and extends into the interior of the lid 56 and terminates atsecond end 152 b. In this embodiment, the second end 152 b of the outletconduit 152 abuts or engages with the second side 146 c of the verticalflow panel 146. At or toward the second end 152 b of the outlet conduit152 are provided one or more inlet apertures through which gases in thehumidification chamber may enter the conduit 152 and may exit thehumidification chamber via the gases outlet 150. In this embodiment, theoutlet conduit 152 is substantially rectangular having lower 152 c andupper 152 d walls and left 152 e and right 152 f side walls which extendalong its length. In this embodiment, two main inlet apertures 154 a and154 b are provided at or towards the second end 152 b of the inletconduit in each of the side walls 152 e and 152 f such that inlets opentoward either the front or rear ends of the lid. In this embodiment, theinlet apertures 154 a, 154 b are substantially rectangular, but may becircular or otherwise. As shown in FIGS. 7, 12 and 19 vertical wallformations 155 a, 155 b extend up from the lower wall 152 c of theconduit in the region of each respective inlet aperture 154 a, 154 b.The wall formations 155 a, 155 b act as water splash barriers and areconfigured to force the gases stream to move up around the wall beforeentering the apertures 154 a, 154 b rather than moving directly into theapertures from the surface of the water directly underneath theapertures. This configuration reduces the likelihood of water beingpicked up or carried by the gases stream (particularly at high flowrates) and entering into the outlet conduit 152. It will be appreciatedthat the inlet conduit 152 need not necessarily extend all the way intocontact with the vertical flow panel 146, and may alternativelyterminate at a position between the vertical flow panel 146 and sidewall 108 of the lid.

Lid Inlet and Outlet Connections

As described above, the gases inlet 140 and the gases outlet 150 haveassociated conduits 142 and 152 for creating the desired gas flow pathwithin the humidification chamber to maximize humidification, althoughit will be appreciated that these conduits are not essential. In analternative embodiment the gases inlet 140 and gases outlet 150 maysimply be apertures in the side walls without conduits extending intothe interior of the humidification chamber.

When inlet and outlet conduits 142, 152 are provided, it will beappreciated that these need not necessarily enter the chamber lidcentrally from opposite sides at a perpendicular angle to the respectiveperimeter walls. The conduits may be located at corners of the lid andmay enter the chamber at any desired angle. Additionally, the conduitsneed not necessarily be straight conduits, but could be non-straight,and include one or more bends or turns.

As will be appreciated, the gases inlet 140 and gases outlet 150 of thehumidification chamber may be connected into the gas flow path of therespiratory device in various ways. It will be appreciated that thegases inlet 140 may be coupled or fluidly connected into the gases flowpath by one or more conduits, connectors, and/or gaskets that arecoupled to the gases flow path exiting the blower, in a sealed ornon-sealed configuration. Likewise, gases outlet 150 may be coupled inany suitable manner, including connectors, conduits and/or gaskets in asealed or non-sealed configuration to the gas flow path leading to thegases outlet of the respiratory device, which is in turn connected to apatient interface, such as a flexible gases delivery conduit and userinterface, as previously discussed.

In this embodiment, as described with reference to FIG. 2 previously,the chamber is retained within a sealable humidification compartmentcomprising a gases inlet that is fluidly connected to the blower outletand a gases outlet that is fluidly connected to the main gases outlet ofthe respiratory device, which is typically coupled or connectable to apatient interface. In this embodiment, the gases inlet 140 of thechamber is not sealingly connected to the inlet of the compartment butrather open to the pressurized gases entering the sealed compartment.Alternatively, a sealed connection between the inlet of the chamber andcompartment may be employed. In this embodiment the gases outlet 150 ofthe chamber is preferably sealingly connected or coupled via a gasket orother sealed connection configuration to the gases outlet of thehumidification compartment or at least closely aligned to each other tominimize gas bypassing the chamber directly to the compartment outlet.

Hinge and Clip

As previously mentioned, the lid 56 is hingedly coupled or connected tothe cradle 52 such they are moveable between an open position in whichlid is pivoted away from the cradle to enable the water tub 54 to beremoved from the cradle (or to allow the tub to be filled with water orcleaned with the lid open) and a closed position in which the lid pivotsinto engagement with the cradle to encapsulate and secure the water tubbetween the lid and cradle. In this embodiment, the lid 56 is pivotalabout a hinge located at the rear end of the chamber between the closedposition or configuration as shown in FIG. 3 and the open position orconfiguration as shown in FIGS. 13-16, for example.

In this embodiment, one or more hinges are located at the rear end ofthe humidification chamber which are configured to hingedly couple thelid 56 to the cradle 52. Referring to FIGS. 8, 15 and 16, in thisembodiment, a single elongate living hinge 160 extends along a portionof the rear end of the humidification chamber between the lid 56 andcradle 54. In particular, the living hinge 160 is a thin flexibleplastic hinge that is integrally formed and coupled between a portion ofthe upper edge 76 e of the rear wall 76 of the cradle and a portion ofthe ledge 105 at the rear end of the lid 56. However, it will beappreciated that two or more hinges may be provided along the rear endof the humidification chamber between the lid and cradle and the hingesneed not necessarily be integrally formed living hinges but may behinges or hinging mechanisms that are formed separately and attached orfixed to the lid and cradle.

To secure the humidification chamber in the closed configuration one ormore operable clips or clipping mechanisms are provided and are operablebetween a latched or locked position for securing the humidificationchamber in a closed position, or an unlatched or unlocked position toenable lid 56 to be pivoted away from the cradle into the open positionor configuration.

Referring to FIGS. 9 and 17, in this embodiment, a single operable clip170 is provided or fixed to the lid 56 and which is resiliently moveablebetween an engaged position and disengaged position with a complimentarycatch 172 provided on the cradle 52. In particular, the clip 170 isprovided in a central location on the front wall 102 of the lid 56.Referring to FIG. 17, in this embodiment the operable clip 170 is in theform of a torsion clip that is moveable between an engaged anddisengaged position relative to the complimentary catch 172 provided onthe cradle 52. The clip 170 comprises a user contact portion 174 thatmay be pressed by a user to move or pivot the clip into a disengagedposition and an engagement tab portion 176 which comprises an engagementaperture 176 a. In use, the catch 172 is a protrusion or engagementformation that protrudes from the front wall 74 of the cradle and isaligned with the clip such that it engages into engagement aperture 176a of clip 170 when the clip is in a latched or locked position tothereby secure the lid 56 to the cradle 52.

As shown, the clip 170 is mounted to the lid 56 via torsion members 178a, 178 b which extend from each side of the clip at an intermediateposition between the end of engagement tab portion 176 and user contactportion 174. The torsion members 178 a, 178 b are longitudinally alignedand define a pivot axis DD about which the clip 170 may pivot or rotaterelative to the lid 56 between a rest (engaged, latched) position shownand an unlatched or disengaged position to enable release of the lidfrom the cradle. As shown, the user contact portion 176 is locatedadjacent front wall 102 of the lid while the engagement tab portion 176extends downwardly below the ledge 105 and lower edge of the lid 56. Thetorsion members 178 a, 178 b each extend between a respective supportstrut 180 a, 180 b provide on the front wall 102 and a side of the clip170. In this embodiment, the torsion members 178 a, 178 b aresubstantially cylindrical (although could have a differentcross-sectional shape along their length like square, rectangular orotherwise) and are configured to provide a small degree of twist or flexabout their longitudinal axis to thereby enable the clip to pivot orrotate about the pivot axis DD. As shown, the clip 170 is biased into ortoward its rest position by the torsion members 178 a, 178 b.

In use, when the lid 56 is moved from the open position to the closedposition the tip of the engagement tab 176 engages a camming surface 172a (see FIG. 14) on the catch 172 which causes the clip to pivotoutwardly away from the lid front wall 102 in direction F as shown inFIG. 17. Once the lid 56 is brought into full engagement with the cradle52, the catch 172 snaps into full engagement with the engagementaperture 176 a of the engagement tab portion 176 to thereby allow theclip to return and spring-back into its rest position thereby latchingthe lid securely to the cradle without the user needing to operate theclip in order to engage it with the aperture. To release the clipmechanism to enable the humidification chamber to be opened, a usersimply presses upon the user contacting portion 174 to move it towardthe front wall 102 of the lid in direction E as shown. This causes theengagement tab to again rotate in direction F away from the front wallabout the pivot axis DD to thereby disengage the engagement aperture 176a from the complimentary catch 172, thereby enabling the lid 56 to befully pivoted away from the cradle 52 into the open configuration. Oncethe user releases the pressure on the user contacting portion 174, theclip reverts back to its rest position ready for latching again when thehumidification chamber is closed.

As shown in FIG. 17, the front wall 108 of the lid is provided with twolimit protrusions 182 on the front wall of the chamber behind the usercontacting portion 174, which act to stop the user from over-rotating ortwisting the clip to prevent breakage of the clip mechanism. Referringto FIG. 14, guide formations 184 are optionally provided on either sideof the catch 172 which protrude from the front wall 74 of the cradle 52.In use, the guide formations 184 are displaced a sufficient distanceapart such that the engagement tab portion 176 of the clip may fitbetween the guide formations 184 when in the engaged position.

The clip 170 is mounted to the lid and the catch 172 to the cradle inthe embodiment shown, but it will be appreciated this may be reversed ifdesired such that the clip may be fixed to the cradle and the catch tothe lid.

It will be appreciated that various other alternative clip arrangementsor mechanisms may be employed for securing the lid 56 to the cradle 52of the humidification chamber. Two or more operable clips or latches maybe provided around the periphery of the humidification chamber on one ormultiple walls as required. Other examples of various clippingmechanisms will be explained with reference to alternative embodimentsof the humidification chamber below and it will be appreciated that suchclipping mechanisms be employed in this first embodiment of thehumidification chamber also.

Sealing

Referring to FIG. 10, in this embodiment there is no flexible seal (e.g.silicone or rubber, or otherwise) provided about the perimeter of thehumidification chamber between the lid 56 and water tub 54. The pressurecreated by the clipping mechanism when the humidification chamber isclosed is considered sufficient to reduce or minimize leakage of gasesand/or water at the interface between the lid 56 and water tub 54. Also,additional downward pressure may be applied upon the lid 54 when locatedwithin the humidification compartment of the respiratory device. Forexample, the lid of the humidification compartment may be configured topress down or engage with the lid 56 of the humidification chamber tothereby exert downward force on the lid 56 into a more tightly closedconfiguration. As the chamber is located in a pressurised humidificationcompartment, the pressure difference between the outside and inside ofthe chamber is negligible or near zero. This substantially neutralpressure differential results in minimal tendency for a flow of air outof or into the chamber via the interface or perimeter boundary betweenthe lid and water tub, and therefore sealing is typically not required.

However, it will be appreciated in alternative embodiments one or moreflexible seals may be provided about the perimeter of the humidificationchamber between the lid 56 and water tub 54 to further minimize anypossible gas and/or water leakage from the humidification chamber at theinterface between the water tub and lid. For example, referring to aperimeter flexible seal may even be mounted to either or both of the rim92 of the water tub 54 or to the lower edge 107 or ledge 105 of the lid56. Referring to FIG. 36, one possible sealed chamber configuration isshown in which a perimeter recess or groove is provided on the undersideof the ledge 105 of the lid about the entire chamber perimeter and aseal, for example a silicone or rubber o-ring or the like, is mounted orlocated within the groove for sealingly engaging with the rim 92 of thewater tub when the chamber is closed.

Alternative Clipping Mechanisms

As mentioned, various alternative clipping mechanisms may be utilizedfor securing the lid 56 to the cradle 52 of the humidification chamber50. Some alternative types of clipping mechanisms will now be explainedby way of example only, although it will be appreciated that theseexamples are not intended to be limiting.

First Alternative Clip Mechanism

Referring to FIGS. 21A-21C, the first alternative clipping mechanismcomprises a clip 190 that is pivotally coupled at the front end wall ofthe lid 56 via a living hinge indicated at 191. As shown, the clip 190is hingedly coupled to the ledge 105 of the lid 56. In this embodiment,the clip 190 comprises a main planar tab portion 190 a which comprises acentral engagement aperture 190 b which is configured to engage with acomplimentary shaped catch or protruding formation 192 provided on thefront wall of the cradle 52. The clip 190 further comprises a downwardlyextending handle or grip portion 190 c. In this embodiment, the fingerhandle 190 c is in the form of a thin plastic flexible U-shaped memberthat extends from the lower edge of the main tab portion 190 a. Inparticular, the handle comprises first and second legs 193 that extenddownwardly from opposite sides of the lower edge of the main tab portion190 a and which are joined by a cross member 194, and which provides agripping aperture 198. The finger handle portion 190 c may be integrallyformed in one piece with the main tab portion 190 a of the clip oralternatively formed separately and attached or secured to the clip.

As shown, the finger handle portion preferably is thinner than thecorresponding main tab portion 190 a such that it is bendable orflexible. In this embodiment, the finger handle 190 c extendssubstantially toward or to the bottom surface of the cradle 52 toprovide for easier user finger access or gripping. This configurationalso allows the user to extend more of their finger/or more than onefinger into the gripping aperture 198 and to use the strength of theirarm to pull the clip open rather than levering with the tip of thefinger and applying most of the load through the first finger joint.Additionally, as shown in FIG. 21C, the front wall of the cradle 52 maybe provided with a recessed portion 195 which is aligned with the handle190 c which enables a user finger access to grip the handle 190 c. Inthis embodiment, the catch formation 192 comprises an elongate formationhaving a triangular cross-section. In particular, a front downwardlyangled front camming surface 192 a extends from the front wall 74 of thecradle and a substantially horizontal engagement surface 192 b isprovided on the underside of the formation. The front edge of theengagement surface 192 b is also provided with a ridge or protruding lipthat extends downwardly and which assists in retaining the clip in anengaged state with the catch formation 192.

In use, the user may push or pivot the clip 190 about its living hingeinto engagement with the catch formation 192 and into a latched positionas shown in FIG. 21A. To release the clipping mechanism, the userapplies force through a finger or fingers to the handle portion 190 c ofthe clip (or the main tab portion 190 a itself if they prefer) in adirection away from the cradle front wall so as to pull the clip free ofthe engagement formation 192 to thereby release the clip and thereby thelid 56 from the cradle 52.

Second Alternative Clip Mechanism

Referring to FIG. 22A, a second alternative clip 200 is shown. The clip200 comprises a main tab portion 201 that is integrally coupled via aliving hinge 202 to the ledge 105 of the front wall 102 of the lid 56 aswith the first alternative clip 190. As before, the living hinge 202 isformed from a portion of plastic having reduced thickness and isflexible such that it enables the clip 200 to pivot relative to the lid56. In contrast to the engagement aperture 190 b of the firstalternative clip 190, a second alternative clip 200 is provided andprotruding engagement formation 203 that is configured to engage withthe complimentary catch formation or aperture provided in the front wallof the cradle (not shown).

Third Alternative Clip Mechanism

Referring to FIG. 22B, a third alternative type of clipping mechanism isshown. The third alternative type clip 210 is similar to the firstalternative clip 190 and comprises the hingedly mounted tab 211 havingan engagement aperture which is configured to engage with a catchformation 212 provided on the front wall of the cradle. No extensionhandle is provided in the tab 211 in this embodiment.

Fourth Alternative Clip Mechanism

Referring to FIGS. 23A and 23B, a fourth alternative type of clippingmechanism is shown. The fourth alternative type clip 290 is similar tothe first alternative clip 190 and like reference numerals representlike features. The clip 290 comprises a hingedly mounted tab which doesnot have an extension handle. Rather, the tab has a first uppervertically oriented portion 291 that is hingedly coupled to the lid anda lower larger angled portion 292 that extends at an angle away from theupper portion. The upper portion 291 provides the engagement aperturefor engaging with the catch formation 192 on the front wall of thecradle as previously described. In the engaged position shown, the lowerangled portion 292 of the tab is angled outwardly or away from the wallof the cradle 52 such that a gripping recess or access cavity is formedbetween the lower angled portion 291 and recessed portion 195 on thefront wall to enable a user to grip and pull the tab to disengage theclip when desired.

Alternative Water Level Indicators

It will be appreciated that various other water level indicators toassist the user in identifying when they have filled the water tub tothe maximum water level line could be used, some non-limiting examplesof which will now be explained by way of example.

First Alternative Water Level Indicator

Referring to FIGS. 24A and 24B, a first alternative water levelindicator 220 is shown and which is a variant of the tab water levelindicator 130 previously described. Like reference numerals refer tolike components and features. In this variant, an additional verticalsupport strut or member 221 extends downwardly from the underside of thelid 56 and joins the terminating end of the tab 134 to strengthen thewater level indicator and the angle of the tab.

Second Alternative Water Level Indicator

Referring to FIGS. 25 and 26, a second alternative of water levelindicator 230 is shown. The water level indicator 230 is a conical waterlevel indicator that comprises a hollow cylindrical formation 231extending downwardly from the upper main portion of the lid and whichterminates in a conical end portion 232 comprising indicators or indiciaindicative of at least a maximum water level line as generally indicatedat 233. The water level indicator is formed from transparent material,such as transparent plastic. The steepness of the cone portion 232 maybe varied to alter the amount of warning the user gets as they approachthe maximum water level line. The steeper the angle the more warning isprovided, relative to a shallower cone in which less warning isprovided. In this embodiment, the lid 56 is provided with a single waterfill aperture generally indicated at 234.

Third Alternative Water Level Indicator

Additionally or alternatively, in other embodiments a water levelindicator line or lines may be provided on the inner surface of theperimeter walls of the water tub, for example by printing of the linesonto the surface or otherwise pressing or forming the lines into thewall inner surface of the water tub. Such water level indicator linescan be viewed with the lid open such that water can be poured directlyinto the water tub up to the maximum water fill line on the tub. In suchembodiments, separate water fill holes in the lid could be omitted.

Various other humidification chamber embodiments will now be explained,and like reference numerals represent the same or equivalent componentsor features. It will be appreciated that the features and components ofthe various embodiments may be interchanged and/or combined to producefurther variant embodiments.

Second Embodiment Humidification Chamber—with Full Cradle

Referring to FIG. 27A-27C, a second embodiment of the humidificationchamber 300 will be explained. The humidification chamber 300 issubstantially similar to the first embodiment. As shown, the lid 56 issubstantially similar to the first embodiment although it comprises adifferent clip mechanism 310 on the front wall. In this embodiment, theclip 310 is a U-shaped member mounted to the front wall and which has adegree of flex about the axis indicated at II on FIG. 27B. As shown onFIG. 27A, the clip 310 engages securely with a catch formation 312.Referring to FIG. 27C, the catch formation comprises an elongateformation having a substantially triangular cross-section. Inparticular, an angled front camming surface 314 extends downwardly andoutwardly from the front wall and a substantially horizontal engagementsurface 316 returns back to the front wall from the lower edge of thefront camming surface 314. The U-shape clip 310 comprises two verticallegs 318 which extend downwardly from the lid and are joined by across-member 320. In use the cross-member 320 engages with the cammingsurface 314 of the catch formation 312 as the lid is brought intoengagement with the cradle 352 until snapping or locking into fullengagement with engagement surface 316.

As to other aspects, the second embodiment humidification chamber 300 issubstantially similar to the first embodiment, and comprises a plasticlid 56 that is hingedly coupled with a plastic cradle 352 which receivesa metal water tub of the type previously described. The primarydifference of the second embodiment humidification chamber 300 is thatthe cradle is substantially continuous about the peripheral wall of thewater tub such that it substantially encapsulates and surrounds theentire water tub peripheral wall surface.

Third Embodiment Humidification Chamber—with Overmolded Heater Plate

Overview

Referring to FIGS. 28A-28T, a third embodiment humidification chamber400 will be described in further detail. The humidification chamber 400is similar in overall shape to the previous embodiments, and whereapplicable similar features are represented by similar drawing referencenumerals. It will be appreciated that the description of the previousembodiments in relation to similar features, including variants oralternatives, also applies to this embodiment and will not be repeated.The following description focuses on the differences of the thirdembodiment relative to the previous embodiments.

The primary difference with the third embodiment humidification chamber400 is that it is a two-part chamber assembly, rather than a three-partchamber assembly like the previous embodiments. The phrases “two-part”and “three-part” assemblies are intended to refer to the number of maincomponents of the assembly, regardless of whether they are integrallyformed or otherwise connected, coupled or assemble together. Inparticular, the previous embodiments relate to three-part chamberassemblies comprising: an upper part (lid—part one) which is hingedlycoupled to open and close relative to a lower part (cradle—part two)which releasably receives and retains a separate water tub (part three).In contrast, this third embodiment humidification chamber 400 is atwo-part assembly comprising the upper part in the form of a lid 456(part one) that is hingedly coupled at one side to a lower part that isthe form of a water tub 452 (part two) comprising a thermally conductivemetallic heater plate in its base surface.

In this embodiment, the lid 456 and water tub 452 (except the metallicheater plate) are formed of a rigid plastic by injection moulding,vacuum forming, or some other suitable production process, in a similarmanner to the formation of the lid and cradle of the previousembodiments. Typically, the lid 456, water tub 452, and hinged coupling160 between the lid and water tub are integrally formed together as asingle item, although in alternative embodiments the lid and water tubmay be formed as separate parts and then hingedly coupled via one ormore separate hinging components or assemblies. The water tub and/or lidmay be substantially transparent or formed as opaque depending on designrequirements.

Like the previous embodiments, the humidification chamber 400 isoperable or moveable between a closed position in which the lid 456 issecured to the water tub 452 to create an enclosed chamber (as shown inFIGS. 28A and 28B for example) and an open position or configuration asshown in FIGS. 28L-28N in which the lid 456 is displaced or rotatedabout the hinge 160 away from the water tub to open the chamber foraccess. One or more operable clips 290 or latches are provided at thefront end of the humidification chamber for securing or locking thehumidification chamber into the closed position ready for insertion andoperation within a respiratory device as previously discussed.

Water Tub

Referring to FIGS. 28A, 28B, 28L, and 28M, the water tub 452 comprises abase surface 470 from which upright sidewalls extend about the peripheryof the base surface. As shown, the water tub comprises front 474 andrear 476 walls at the front and rear ends of the humidification chamberrespectively, and first 475 and second 477 sidewalls extending along thegases inlet and gases outlet sides of the humidification chamberrespectively.

Referring to FIGS. 28D, 28E, and 28F, one or more of the walls orportions of the walls may be provided with a reinforcing profile that isconfigured to resist bending or deformation of the wall surfaces. Inthis embodiment, each of the sidewalls 475, 477 are provided withreinforced portions or regions 478, 479 respectively comprising acorrugated or undulating surface profile of alternate furrows andridges. In this embodiment, the furrows and ridges have a verticalorientation, but it will be appreciated that a horizontal orientationmay be used in the alternative if desired. In this embodiment, thethickness of the sidewalls in the reinforced or corrugated regions issubstantially uniform such that the ridges and furrows and thetransition zones between the ridges and furrows are of a substantiallysimilar wall thickness as can be seen in FIG. 28D. In alternativeembodiments, the thickness of the sidewalls in the reinforced regionsmay be non-uniform. In this embodiment, the height of each corrugatedregion extends on the sidewalls from the base surface to an intermediatepoint below the edge or rim of the water tub as shown in FIGS. 28E and28F, but it will be appreciated that the corrugated region may start ata point above the base surface or alternatively the corrugated regionmay extend the entire height of the sidewalls if desired. In alternativereinforcing profiles, spaced-apart reinforcing ridges or ribs, whethervertically or horizontally oriented, or may be provided on one or moreportions of the side walls, on either the inner or outer surfaces, orboth. In such embodiments, the ridges or ribs increase the thickness ofthe wall in the region of the ridge or rib. In other alternativeembodiments, the sidewalls of the water tub 452 may be stiffened orreinforced to prevent or minimise bending and/or deformation with aperimeter ledge, lip, or rim extending or protruding outwardly from orat the top perimeter edge of the water tub sidewalls. The rim may be ofthe type or form shown at 92 or 52 a in FIG. 36 for example, i.e.integrally formed about the upper perimeter edge of the sidewalls. Thereinforcing rim may be provided in combination with the reinforcedregions of the sidewalls or as an alternative instead of the reinforcingregions.

Referring to the side elevation in FIGS. 28E-28H, in this embodiment thehumidification chamber 400 comprises a convex or domed base surface 470that is curved or rounded outward toward an apex defined by a centralheater plate, discussed further next. In alternative embodiments, thebase surface 470 may be substantially flat.

Referring to FIGS. 28D, 28L, and 28M, the base surface 470 of the watertub 452 is provided with a centrally located metallic or thermallyconductive heater plate 494. In this embodiment, the heater plate 494 iscircular and joined or fixed into a complementary circular apertureprovided in the center of the base surface 470 of the plastic water tub452 by overmoulding. The heater plate may be formed of a rigid andthermally conductive material, and is typically pressed or shaped fromsheet metal, such as aluminum, stainless steel or any other suitablematerial, or could be formed by die casting for example. In thisembodiment, the heater plate 494 and complementary aperture in the basesurface 470 of the water tub are circular, although it will beappreciated that this shape may be varied to provide an integratedheater plate surface of any other alternative shape, including square,rectangular, or any arbitrary shape. In this embodiment, the heaterplate 494 is substantially flat prior to the overmoulding process butmay have a slightly outwardly domed or convex profile caused bycompression force from the surrounding domed base surface after theovermoulding process. The compression force or bias which causes theslightly outwardly convex engagement surface of the heater plate reducesor resists the likelihood of the heater plate being deformed inwardlyovertime and usage as a deformed inwardly concaved engagement surfacewould reduce the contact surface area of the heater plate with theheater pad it sits on in the humidification compartment, which wouldreduce the heat transfer efficiency of the configuration.

In this embodiment, the heater plate 494 is provided with a maincircular contact surface 495 that is configured to protrude or extendbeyond the surrounding plastic base surface 470 of the water tub 452, toencourage full engagement and heat transfer when the chamber sits on acomplementary shaped heater pad in the bottom of the humidificationcompartment. In this embodiment, the heater plate further comprises anupright or substantially vertical wall portion 496 that extends aroundthe periphery of the main contact surface portion 495 and an outersubstantially horizontal peripheral coupling surface or ledge portion497 that extends outwardly from the top of the wall portion 496 aroundthe perimeter of the heater plate. As shown, the main contact surfaceportion 495 and outer coupling ledge 497 extend in substantiallyparallel planes but are displaced vertically from each other by theheight of the vertical wall portion 496. As shown, it is the couplingledge 497 of the heater plate 494 that is coupled or fixed to thesurrounding plastic about the periphery of the central aperture of thebase surface 470 by overmolding. In particular, an engagement portion471 of the base surface material about the periphery of the centralaperture of the base surface 470 is moulded over at least a portion ofthe coupling ledge 497 of the heater plate 494, about its entireperiphery.

Referring to FIG. 28J, in this embodiment the overmoulding process isconfigured to vary the thickness of the engagement portion 471 of thebase surface relative to the remainder of the base surface. In thisembodiment, the overall thickness 401 of the engagement portion 471 thatis moulded over at least a portion of the coupling ledge 497 of theheater plate 494 is larger than the thickness 402 of the remaining basesurface 470 of the water tub. This configuration assists in reducinglifting of the plastic of the base surface 470 away from the couplingledge 497 of the heater plate after moulding, which in turn reduces theamount of hard water deposit ingress at the transitional interfaceregion between the metal heater plate and plastic base surface. In onearrangement, the thickness 403 of an upper portion of the engagementportion 471 above the coupling ledge 497 of the heater plate 494 issimilar to or at least as thick as the thickness 402 of the remainingbase surface, to reduce or minimise lifting of the upper portion awayfrom the coupling ledge 497. As shown, in this embodiment, the thickness404 of a lower portion of the engagement portion 471 below the couplingledge 497 may be of smaller thickness than the thickness 403 of theupper portion of the engagement portion 471 of the base surface 470. Inalternative embodiments, the thickness 404 of the lower portion of theengagement surface may also be similar to or at least as thick as thethickness 402 of the remaining base surface to reduce or minimizelifting of lower portion from the coupling ledge.

It will be appreciated that in alternative embodiments, the heater platemay be a substantially flat circular plate which is secured within thecentral aperture of the base surface by overmoulding such that it issubstantially flush with the remainder of the base surface rather thanprotruding as described above.

Referring to FIG. 28L, in this embodiment, the water tub 452 is alsoprovided with a continuous horizontal step formation 472 extending aboutthe perimeter of the inner sidewall surface. The step formation isdisplaced a uniform height from the base surface of the water tub aboutthe inner perimeter. The step formation is integrally formed into thesidewalls and may be in the form of an angled step as shown in FIG. 28I.In this configuration, the step formation 472 is located at a heightfrom the base surface that corresponds to a maximum fill line. When thelid of the chamber is in the open position, the user may fill the watertub with water up to the level of the step formation, as an alternativeoption to using the water fill holes.

Lid

The lid 456 of the third embodiment humidification chamber 400 issubstantially similar to the lid 56 of the previous embodiments,although there are some main differences, which will be explained in thefollowing. It will also be appreciated that the third embodimenthumidification chamber could also use the same lid 56 as previouslydescribed.

Referring to FIGS. 28C, 28I and 28L, in this embodiment the lid 456 isprovided with tab water level indicators 220 of the type explainedpreviously with reference to FIGS. 24A and 24B. In particular, the tabwater level indicators 220 comprise an angle tab 134 which is suspendedbelow each water fill aperture 120 by upright support members 132, 221at each end. In this embodiment, the indicia “MAX” for maximum isprinted backwards on the underside surface of the tab portions 134 asshown in FIG. 28L. At least the tab portions 134 are formed oftransparent plastic such that the indicia “MAX” is presented to the userthrough in the correct readable format when viewed through the waterfill holes 120.

Referring to FIGS. 28E and 28C, the inlet side perimeter wall 106 of thelid 456 is provided with a projection or projections 407, such as bumpsor ridges or formations, that extend from the surface of the perimeterwall. In this embodiment, a protrusion 407 is provided on each side ofthe central inlet aperture 140 of the lid for engaging with alignedrails provided on the inner inlet gases side wall of the humidificationcompartment, which will now be explained. Referring to FIG. 28O shows alower part of a humidification compartment 800 that is shaped anddimensioned with a complementary cavity 802 that receives and retainsthe humidification chamber 400. The lower part of the humidificationcompartment may be part of the housing or body of a respiratory deviceof the type previously described. As previously described with referenceto FIG. 2, the humidification compartment may further comprise anopenable lid for sealing or enclosing the compartment once thehumidification chamber 400 is installed in the cavity. As shown, twovertical rails 406 protrude from the inner wall surface of thehumidification compartment on each side of the gases inlet 804, whichreceives a flow of gases from the blower of the respiratory device asexplained previously with reference to FIG. 2. In this embodiment, eachrail 806 extends from a first upper end at or toward the height of thegases inlet 804 and a second lower end at or toward the floor surface ofthe compartment. In this embodiment, referring to FIGS. 28o and 28T)each rail comprises a first short start ramp portion 806 a that tapersor slopes outwardly from the wall surface, and then extends into asecond longer return ramp portion 806 b that tapers or slopes backtoward the inner wall surface. In operation, the protrusions 407 on thegases inlet side of the humidification chamber 400 are aligned withengagement rails 806 on the inlet side of the humidificationcompartment. As the humidification chamber 400 is lowered or inserteddown into the humidification compartment, the protrusions 407 abut orengage with their respective rail 806, and the rails urge the chamber400 toward the opposite outlet sidewall of the compartment comprisingthe gases outlet 808, which is shown in FIG. 28P. This configurationassists in urging and holding the gases outlet 150 of the chamber intosealing engagement or connection with the gases outlet 808 of thecompartment once the chamber is full inserted or installed. In thisconfiguration, the gases outlet 808 of the compartment is provided witha seal 810 that extends about the perimeter of the gases outlet 808. Theseal may be an elastomer or rubber component or insert for example. Aswill be explained next, in this embodiment, the gases outlet 150 of thechamber is provided with an engagement surface 430 that sealinglyengages with the seal 810 about the perimeter of the gases outlet 808 tothereby create a sealed connection between the outlets. In alternativeembodiments, it will be appreciated that the seal may be provided on thegases outlet 150 of the chamber, or both the outlets of the chamber andcompartment may have complementary seals.

Referring to FIGS. 28F, 28K, and FIGS. 28P-28S, in the third embodimenthumidification chamber 400 the gases outlet 150 on the outlet sideperimeter wall 108 of the lid 456 comprises an engagement surface orformation 430 about the perimeter of the aperture 150. The engagementsurface 430 is configured to sealingly engage with the seal 810 gasesoutlet 808 of the humidification compartment 800 when the humidificationchamber 400 is installed within the compartment. In this embodiment, thegases outlet 150 is substantially rectangular and therefore theengagement surface 430 is also substantially rectangular and comprisesupper 431 and lower 432 horizontal portions extending along the upperand lower perimeters of the gases outlet 150 and side vertical portions433, 434 along the side perimeter portions of the gases outlet 150. Inthis embodiment, the engagement surface 430 is substantially planarabout the perimeter or periphery of the gases outlet 150 such that itmay sealingly engage with a complementary seal 810 or outlet surfaceassociated with the gases outlet 808 of the humidification compartment800. In the arrangement shown, the engagement surface 430 is preferablyangled or tilted outward relative to the vertical outlet side perimeterwall 108. In particular, as shown more clearly in FIG. 28K, theengagement surface 430 is angled such that the upper portion 431 isdisplaced outward from the outlet side perimeter wall 108 further thanthe lower portion 432. In this arrangement the engagement surface 430can be considered as being tilted or pivoted outward about a horizontalaxis extending across its surface such that the upper portion of theengagement surface protrudes or is displaced further from the outletside perimeter wall 108 of the lid 456 than the lower portion or region432 of the engagement surface. It will be appreciated that the sameprinciples may be applied should the gases outlet and engagement surfacebe circular or otherwise shaped. The angled engagement surface 430assists in enabling the humidification chamber to be easily received orinserted into the complementary humidification compartment 800 andassists in creating a sealed engagement or connection between the gasesoutlet 150 of the chamber and the gases outlet 808 of the humidificationcompartment 800.

Referring to FIG. 28L, the vertical flow panel 146 of the lid 456 ismodified relative to the previous embodiments. In this embodiment, thevertical panel or plane 146 additionally comprises a pair of baffleportions or vanes 435 which extend along the side edges 146 of the flowpanel 146 along the full height (H) of the flow panel, and which act asflow deflectors or guides. The side baffles 435 protrude or extend awayfrom the first side surface 146 b of the flow panel 146 along each ofits side edges. In particular, the side baffles 435 extend substantiallyperpendicular to the flow plane 146 such that they extend towards theinlet side of the lid. In this arrangement, the side baffles 435 of thevertical flow panel 146 have a width W2 (extending in a directionperpendicular to the surface of the flow panel) that is substantiallysmaller than the overall width W of the vertical flow panel. In use, theside baffle portions or surfaces 435 are configured to minimise orprevent air flow exiting the inlet conduit 142 from flowing directlyaround the side edges 146 e of the vertical flow panel toward the gasesoutlet conduit 152, which a flow path that results in reducedhumidification. The side baffles 435 force or encourage the air tocirculate back toward the inlet side of the humidification chamber andlengthen the general air flow circulation path in the chamber before thegases exit the chamber to enhance the moisture absorption. As previouslydescribed, the height (H) of the flow panel 146 is typically configuredsuch that it protrudes or penetrates sufficiently deeply into thesurface of the water to prevent gases exiting the inlet conduit 142 fromshortcutting underneath the lower edge 146 a and directly to the outletconduit 152.

Hinge and Clip

As previously mentioned, the upper part or lid 456 is hingedly coupledor connected to the lower part or water tub 452 such that they aremoveable between an open position in which the lid is pivoted away fromthe water tub (to allow the tub to be filled with water or cleaned withthe lid open) and a closed position in which the lid pivots intoengagement with the water tub to close the chamber. In this embodiment,lid 456 is hingedly coupled to the water tub 452 in a similar manner tothe hinging coupling between the lid and cradle of the previousembodiments. In particular, the lid 456 is pivotable about a hingelocated at the rear of the chamber between the closed position orconfiguration shown in FIGS. 28A and 28B and an open position orconfiguration as shown in FIGS. 28L-28N, for example. As shown in FIGS.28A, 28G and 28M, in this embodiment the hinge is a single elongateliving hinge 160 that extends along a portion of the rear end of thehumidification chamber between the lid 456 and water tub 452, and is ofa form as previously described in the previous embodiments.

To secure the humidification chamber in the closed configuration, one ormore operable clips or clipping mechanisms are provided and are operablebetween a latched or locked position for securing the chamber in theclosed position, or in an unlatched or unlocked position to enable thelid 456 to be pivoted away from the water tub into the open position orconfiguration. Referring to FIGS. 28B, 28H, 28M and 28N, in thisembodiment the humidification chamber comprises a single operable clip290 and complementary catch formation 192 of the type described withreference to FIGS. 23A and 23B. In particular, the clip 290 is pivotablymounted to the lid and is moveable into engagement with the catch 192 tosecurely close the chamber or may be disengaged or released from thecatch 192 to enable the chamber to be opened. As shown in FIG. 28H, arecessed portion 195 is provided on the front wall of the water tub 452in the vicinity of the clip 290 to enable a user to grip and pull thetab to disengage the clip from the catch formation 192 when desired.

Sealing

As with the previous embodiments, the third embodiment chamber 400 neednot necessarily be sealed between the lid 456 and water tub 452.However, it may be sealed if desired as shown in this embodiment.Referring to FIG. 28I, the ledge 105 of the lid 456 is provided with orforms a perimeter groove or recess and a seal 99 is mounted in thegroove about the perimeter of the lid in a similar configuration to thatdescribed with reference to the embodiment of FIG. 36. As shown, theseal 99 engages with the upper surface or rim 461 of the perimeter wallof the water tub 452 when the chamber is closed to seal the chamber. Theother seal configurations discussed with reference to FIG. 36 may alsobe employed in alternative configurations.

Fourth Embodiment Humidification Chamber—with Sleeve

Referring to FIGS. 29A and 29B, the fourth embodiment humidificationchamber 500 is a variant of the second embodiment humidification chamber300. In this embodiment, the lid 56 is not hingedly coupled at one endto a full cradle but rather to a sleeve 552 in the form of a continuousperimeter wall that encircles or extends about the entire peripheralwall of the water tub 54 as shown. In particular, the sleeve 552 leavesthe entire base surface 54 in the water tub exposed. The sleeve 552 ispreferably formed of the same material as the lid, for example injectionmolded from plastic or similar. The height of the sleeve as indicated at554 may be varied as desired. In this embodiment, the sleeve extendssubstantially from the upper edge of the rim of the water tub to thebase surface of the water tub, but may be thinner and extend only partway down the peripheral wall from the upper edge in alternativeembodiments. As shown in FIG. 29B, the sleeve is prevented from liftingor sliding off the water tub 54 by virtue of the lip or rim 92 extendingoutwardly from the upper edge of the water tub 54. Otherwise, thehumidification chamber is substantially similar to the previousembodiment and is provided with a living hinge coupling the lid to thesleeve 52 along the rear end (not shown) and a clipping mechanism 560 atthe front, which in this embodiment is of a form described with respectto FIGS. 21A-21C.

Fifth Embodiment Humidification Chamber—with Internal Clips

Referring to FIGS. 30A-30C, the fifth embodiment humidification chamber600 (see FIG. 30C) comprises a plastic lid 602 which is releasablycoupled to a metal water tub 604 (see FIG. 30B) via internal clips. Theplastic lid 602 is substantially similar to the lids of the previousembodiments although comprising a slightly different water levelindicator configuration. In particular, there is a water fill hole 606centrally located toward one end of the lid and a conical water levelindicator 608 located toward one corner of the opposite end of the lid.Additionally, a finger gripping recess 610 is provided centrally on thewater level indicator end of the lid. The internal structure of the lid602 is otherwise similar, including the gases inlet, gases outlet andvertical flow plane configuration.

The water tub 604 is entirely formed from metal such as stainless steel,aluminum or similar. Optionally, a sleeve or cradle of insulatingmaterial such as plastic or other thermally insulating material may beprovided on the outer peripheral walls and/or underside surfaces of themetal tub to prevent user from burning their hands if picking up themetal tub, although the user may pick up the metal tub via the lid bygripping of the water fill aperture 606 and the figure grip recess 610with a finger and thumb for example.

The lid 602 is not hingedly coupled to the water tub 604 but rather iscompletely detachably removable from the water tub. Each end of the lidis provided with clips or engagement protrusions 612 (only one endvisible) which are configured to engage into the complimentary recesses614 provided at each end of the water tub 604 at or toward the upperedge of the water tub. Assembling the lid 602 with the water tub 604requires the user to press the lid until the clip formations 612 engagein the complimentary recesses 614. To release the lid, the user pullsthe lid in a vertical direction from the water tub with sufficient forceto disengage the clip formations 612 from the recesses 614.

Sixth Embodiment Humidification Chamber—with Ducted Lid

Referring to FIGS. 31A-35, the sixth embodiment humidification chamber700 will be described. This embodiment comprises a plastic lid 702 whichclips into a complimentary shaped metal water tub 704 by a similarmanner described above with reference to the fifth embodimenthumidification chamber 600. FIG. 31A shows the inlet aperture 706 of thehumidification chamber and FIG. 31B shows the gases outlet 708 of thehumidification chamber.

Referring to FIG. 32, in this embodiment the water tub is formed frommetal or other thermally conductive material such that it may directlycontact or sit on a heater base. Engagement apertures 710 are providedat each end of the water tub for receiving complimentary clips resilientclips 730 provided in the lid 702 to secure the lid to the water tub.The gases inlet 706 is an aperture provided through the peripheral wallof one side of the water tub toward a corner at the upper edge of thewater tub, although it may be centrally or otherwise be located. On theopposite side of the water tub is provided a cut out or recess 712within which the gases outlet 708 of the lid may sit when the lid isengaged with the water tub in a closed or assembled configuration.

Referring to FIGS. 33-35, the lid 702 comprises an upper frame member714 that is coupled to a lower frame member 716 via an internal verticalwall 718. The internal wall is inset or displaced from the edge of theframe members 714, 716 about the periphery of the lid such that aperimeter gases flow channel is formed about a substantial portion ofthe perimeter within the lid when engaged with the tub 704. As the gasesenter the perimeter channel via the inlet 706, the gases flow about thechannel and enter into the internal volume of the humidification chambervia a series of one or more internal inlet apertures 720 formed throughthe internal wall 718 of the lid. In this embodiment, the bulk of theinlet apertures 720 are provided on the inlet side wall, but one or moreapertures may be spread about the entire peripheral surface of theinternal wall, including the end walls and the opposite side walllocated adjacent the outlet, as indicated in FIG. 35 at 720, althoughnot visible. Additionally or alternatively, inlet apertures could beprovided through the lower frame member 716 about at least a portion ofthe periphery of the lid.

Referring to FIG. 35, the internal or underside surface of the lidwithin the internal perimeter wall 718 is provided with a configurationof vertical flow planes 722 associated with each internal inlet aperture720 and which forces the incoming gases streams down into the volume ofthe humidification chamber to enhance the humidification process. Thegases outlet 708 comprises an outlet conduit 724 that extendshorizontally into the internal volume of the lid from the aperture 708and which terminates with inlet apertures 726 which enables thehumidification gases to enter the outlet conduit 724 and exit thehumidification chamber via the gases outlet 708. Referring to FIG. 33,centrally located at each end of the lid 702 is a resilient spring clip730 comprising a clipping formation 732 that is configured to engage inthe complimentary engagement aperture 710 of the water tub to secure thelid to the water tub.

EMBODIMENTS

1. A humidification chamber for humidifying gases, comprising: a watertub that is configured to receive a volume of water; a cradle definingan open cavity within which the water tub is received; a lid hingedlycoupled to the cradle for enclosing the water tub to define the interiorvolume of the humidification chamber and which is movable between aclosed position in which the water tub is closed by the lid and an openposition in which the water tub is open; one or more operable clips forsecuring the lid in the closed position; a gases inlet for receiving aflow of gases into the interior volume of the humidification chamber;and a gases outlet through which a humidified flow of gases may exit theinterior volume of the humidification chamber.2. A humidification chamber according to paragraph 1 wherein the lid andcradle are formed of rigid plastic.3. A humidification chamber according to paragraph 1 or paragraph 2wherein the lid and cradle are hingedly coupled by a living hinge andare integrally formed as a single item.4. A humidification chamber according to any one of the precedingparagraphs wherein the water tub is formed of a thermally conductivematerial.5. A humidification chamber according to paragraph 4 wherein the watertub is formed from metal.6. A humidification chamber according to any one of the precedingparagraphs wherein the water tub is defined by a base surface and aperimeter wall that extends upwardly from the base, and wherein thecradle comprises a complementary base surface and upwardly extendingperimeter wall and wherein the perimeter wall of the cradle isdiscontinuous about the perimeter of the cradle so as to expose one ormore portions of the peripheral wall of the water tub retained withinthe cradle.7. A humidification chamber according to paragraph 6 wherein a heattransfer contact surface protrudes from the base surface of the watertub and the cradle is provided with a complementary aligned aperturethrough which the contact surface of the water tub extends such that itprotrudes beyond the underside of the base surface of the cradle.8. A humidification chamber according to any one of the precedingparagraphs wherein the water tub is releasably received within thecradle by slidable engagement.9. A humidification chamber according to any one of the precedingparagraphs wherein the gases inlet and gases outlet are provided onopposite sides of the lid.10. A humidification chamber according to paragraph 9 wherein the lidcomprises a vertical flow plane that extends downwardly from theunderside of the lid in a central region of the lid.11. A humidification chamber according to paragraph 10 wherein the gasesinlet is coupled to an inlet conduit that extends between an inlet endat the gases inlet and an outlet end located at or toward an uppercentral region of the interior volume of the humidification chamber andadjacent a first side surface of the vertical flow plane such that theincoming gases flow enters the interior volume of the humidificationchamber at that upper central region.12. A humidification chamber according to paragraph 11 wherein a flowdirector formation in the form of an inverted curved ramp surface islocated between the outlet end of the inlet conduit and the first sidesurface of the vertical flow plane.13. A humidification chamber according to paragraph 11 or paragraph 12wherein the gases outlet is coupled to an outlet conduit that extendsbetween an inlet end located at or toward an upper central region of theinterior volume of the humidification chamber and adjacent a second sideof the vertical flow plane and an outlet end at the gases outlet.14. A humidification chamber according to any one of the precedingparagraphs wherein the lid comprises one or more water fill aperturesand at least one water fill aperture comprising an associated maximumwater level indicator comprising a tab member that is supported from theunderside of the lid such that it extends into the field of view of theinterior volume of the humidification chamber visible directly throughthe water fill aperture.15. A humidification chamber according to any one of the precedingparagraphs wherein the humidification chamber has an overall shapedefined by front and end walls between which side walls extend, and thewalls extending between an upper surface of the lid and base surface ofthe cradle, and wherein the lid is hingedly coupled to the cradle at therear end of the humidification chamber, and at least one operable clipis provided at the front end of the humidification chamber.16. A humidification chamber according to any one of the precedingparagraphs wherein at least one operable clip is provided in the form ofa torsion clip that is mounted to either the lid or cradle and which isconfigured to engage with a catch provided on either the cradle or lid,respectively.17. A humidification chamber according to any one of paragraphs 1-15wherein at least one operable clip is provided that is hingedly coupledto the lid or cradle and which is configured to engage with a catchprovided on either the cradle or lid, respectively.18. A humidification chamber for humidifying gases, comprising: a watertub that is configured to receive a volume of water; a lid hingedlycoupled to the water tub for enclosing the water tub to define theinterior volume of the humidification chamber and which is movablebetween a closed position in which the water tub is closed by the lidand an open position in which the water tub is open; one or moreoperable clips for securing the lid in the closed position; a gasesinlet for receiving a flow of gases into the interior volume of thehumidification chamber; and a gases outlet through which a humidifiedflow of gases may exit the interior volume of the humidificationchamber.19. A humidification chamber according to paragraph 18 wherein the lidis formed from rigid plastic.20. A humidification chamber according to paragraph 18 or paragraph 19wherein the water tub is formed of rigid plastic and comprises a basesurface and a perimeter wall that extends upwardly from the base, andwherein the base surface comprises a heater plate.21. A humidification chamber according to paragraph 20 wherein theheater plate is secured within an aperture of the base surface of thewater tub by overmolding.22. A humidification chamber according to paragraph 21 wherein aperipheral coupling surface of the heater plate is secured within aperipheral engagement portion of the base surface about the aperture ofthe water tub by overmolding such that the thickness of the engagementportion is greater than the thickness of remaining base surface.23. A humidification chamber according to paragraph 22 wherein theengagement portion comprises an upper portion above the coupling surfaceof the heater plate and a lower portion below the coupling surface, andwherein the upper portion is at least as thick as the remaining basesurface.24. A humidification chamber according to any one of paragraphs 20-23wherein the heater plate is metallic.25. A humidification chamber according to any one of paragraphs 20-24further comprising a step formation about the inner surface perimeter ofthe wall of the water tub, the step formation being configured at aheight above the base surface of the water tub corresponding to amaximum fill line indicator.26. A humidification chamber according to any one of paragraphs 20-25wherein the base surface of the water tub is domed such that it curvesoutward toward a central apex defined by the heater plate.27. A humidification chamber according to any one of paragraphs 20-26wherein the perimeter wall of the water tub comprises one or morereinforced regions.28. A humidification chamber according to paragraph 27 wherein thereinforced region(s) of the perimeter wall comprises corrugated surfacesof alternating ridges and furrows.29. A humidification chamber according to any one of paragraphs 18-28wherein the lid and water tub are hingedly coupled by a living hinge andare integrally formed as a single item.30. A humidification chamber according to any one of paragraphs 18-29wherein the gases inlet and gases outlet are provided on opposite sidesof the lid.31. A humidification chamber according to paragraph 30 wherein the lidcomprises a vertical flow plane that extends downwardly from theunderside of the lid in a central region of the lid.32. A humidification chamber according to paragraph 31 wherein thevertical flow plane further comprises a pair of side baffles that eachextend from a respective side edge of the vertical flow plane toward theside of the lid comprising the gases inlet.33. A humidification chamber according to paragraph 31 or paragraph 32wherein the gases inlet is coupled to an inlet conduit that extendsbetween an inlet end at the gases inlet and an outlet end located at ortoward an upper central region of the interior volume of thehumidification chamber and adjacent a first side surface of the verticalflow plane such that the incoming gases flow enters the interior volumeof the humidification chamber at that upper central region.34. A humidification chamber according to paragraph 33 wherein a flowdirector formation in the form of an inverted curved ramp surface islocated between the outlet end of the inlet conduit and the first sidesurface of the vertical flow plane.35. A humidification chamber according to paragraph 33 or paragraph 34wherein the gases outlet is coupled to an outlet conduit that extendsbetween an inlet end located at or toward an upper central region of theinterior volume of the humidification chamber and adjacent a second sideof the vertical flow plane and an outlet end at the gases outlet.36. A humidification chamber according to any one of paragraphs 18-35wherein the gases outlet of the lid comprises an engagement surfaceabout the perimeter of the gases outlet that is tilted outwardly suchthat an upper portion of the engagement surface is displaced furtheroutward from the lid than a lower portion of the engagement surface.37. A humidification chamber according to any one of paragraphs 18-36wherein the lid comprises one or more water fill apertures and at leastone water fill aperture comprising an associated maximum water levelindicator comprising a tab member that is supported from the undersideof the lid such that it extends into the field of view of the interiorvolume of the humidification chamber visible directly through the waterfill aperture.38. A humidification chamber according to any one of paragraphs 18-37wherein the humidification chamber has an overall shape defined by frontand end walls between which side walls extend, and the walls extendingbetween an upper surface of the lid and base surface of the water tub,and wherein the lid is hingedly coupled to the water tub at the rear endof the humidification chamber, and at least one operable clip isprovided at the front end of the humidification chamber.39. A humidification chamber according to any one of paragraphs 18-38wherein at least one operable clip is provided in the form of a torsionclip that is mounted to either the lid or water tub and which isconfigured to engage with a catch provided on either the water tub orlid, respectively.40. A humidification chamber according to any one of paragraphs 18-39wherein at least one operable clip is provided that is hingedly coupledto the lid or water tub and which is configured to engage with a catchprovided on either the water tub or lid, respectively.41. A humidification chamber according to any one of paragraphs 18-40further comprising a seal about the perimeter of the chamber between thelid and water tub to seal the chamber when it is in a closed position.42. A respiratory assistance device configured to provide a heated andhumidified gases stream, comprising: a device gases inlet configured toreceive a supply of gases; a blower configured to generate a pressurisedgases stream from the supply of gases; a humidifier configured to heatand humidify the pressurised gases stream; a device gases outlet for theheated and humidified gases stream; and a flow path for the gases streamthrough the respiratory device from the gases inlet though the blowerunit and humidification unit to the gases outlet, and wherein thehumidifier comprises a sealable humidification compartment that isconfigured to receive and retain a removable humidification chamberaccording to any one of the preceding paragraphs.43. A respiratory assistance device according to paragraph 42 whereinthe humidification compartment comprises a lid that is movable betweenan open position to enable removal of the humidification chamber and aclosed position to seal the humidification chamber within thehumidification compartment.44. A respiratory assistance device according to paragraph 42 orparagraph 43 wherein the humidification compartment comprises a gasesinlet connected to the flow path to receive the pressurised gases streamfrom the blower to create a pressurised humidification compartment and agases outlet connected to the device gases outlet of the flow path.45. A respiratory assistance device according to paragraph 44 whereinthe gases inlet of the humidification chamber is open within thehumidification compartment to receive an incoming flow of gases fromwithin the pressurised humidification compartment.46. A respiratory assistance device according to paragraph 44 orparagraph 45 wherein the gases outlet of the humidification compartmentis sealingly connected to the gases outlet of the humidificationchamber.47. A respiratory assistance device according to any one of paragraphs42-46 wherein the humidification compartment comprises a heater pad uponwhich the humidification chamber sits.48. A respiratory device according to any one of paragraphs 42-47wherein the device is contained within a single housing.49. A respiratory device according to any one of paragraphs 42-48wherein the device is a CPAP respiratory device.

The foregoing description of the invention includes preferred formsthereof. Modifications may be made thereto without departing from thescope of the invention as defined by the accompanying claims.

1. A humidification chamber for humidifying gases, comprising: a watertub that is configured to receive a volume of water; a lid hingedlycoupled to the water tub for enclosing the water tub to define theinterior volume of the humidification chamber and which is movablebetween a closed position in which the water tub is closed by the lidand an open position in which the water tub is open; one or moreoperable clips for securing the lid in the closed position; a gasesinlet for receiving a flow of gases into the interior volume of thehumidification chamber; and a gases outlet through which a humidifiedflow of gases may exit the interior volume of the humidificationchamber.
 2. A humidification chamber according to claim 1 wherein thelid is formed from rigid plastic.
 3. A humidification chamber accordingto claim 1 wherein the water tub is formed of rigid plastic andcomprises a base surface and a perimeter wall that extends upwardly fromthe base, and wherein the base surface comprises a heater plate.
 4. Ahumidification chamber according to claim 3 wherein the heater plate issecured within an aperture of the base surface of the water tub byovermolding.
 5. A humidification chamber according to claim 4 wherein aperipheral coupling surface of the heater plate is secured within aperipheral engagement portion of the base surface about the aperture ofthe water tub by overmolding such that the thickness of the engagementportion is greater than the thickness of remaining base surface.
 6. Ahumidification chamber according to claim 5 wherein the engagementportion comprises an upper portion above the coupling surface of theheater plate and a lower portion below the coupling surface, and whereinthe upper portion is at least as thick as the remaining base surface. 7.A humidification chamber according to claim 3 wherein the heater plateis metallic.
 8. A humidification chamber according to claim 3 furthercomprising a step formation about the inner surface perimeter of thewall of the water tub, the step formation being configured at a heightabove the base surface of the water tub corresponding to a maximum fillline indicator.
 9. A humidification chamber according to claim 3 whereinthe base surface of the water tub is domed such that it curves outwardtoward a central apex defined by the heater plate.
 10. A humidificationchamber according to claim 3 wherein the perimeter wall of the water tubcomprises one or more reinforced regions.
 11. A humidification chamberaccording to claim 1 wherein the gases inlet and gases outlet areprovided on opposite sides of the lid.
 12. A humidification chamberaccording to claim 1 wherein the vertical flow plane further comprises apair of side baffles that each extend from a respective side edge of thevertical flow plane toward the side of the lid comprising the gasesinlet.
 13. A humidification chamber according to claim 1 wherein thegases inlet is coupled to an inlet conduit that extends between an inletend at the gases inlet and an outlet end located at or toward an uppercentral region of the interior volume of the humidification chamber andadjacent a first side surface of the vertical flow plane such that theincoming gases flow enters the interior volume of the humidificationchamber at that upper central region.
 14. A humidification chamberaccording to claim 16 wherein a flow director formation in the form ofan inverted curved ramp surface is located between the outlet end of theinlet conduit and the first side surface of the vertical flow plane. 15.A humidification chamber according to claim 1 wherein the gases outletof the lid comprises an engagement surface about the perimeter of thegases outlet that is tilted outwardly such that an upper portion of theengagement surface is displaced further outward from the lid than alower portion of the engagement surface.
 16. A humidification chamberaccording to claim 1 wherein the lid comprises one or more water fillapertures and at least one water fill aperture comprising an associatedmaximum water level indicator comprising a tab member that is supportedfrom the underside of the lid such that it extends into the field ofview of the interior volume of the humidification chamber visibledirectly through the water fill aperture.
 17. A humidification chamberaccording to claim 1 wherein the humidification chamber has an overallshape defined by front and end walls between which side walls extend,and the walls extending between an upper surface of the lid and basesurface of the water tub, and wherein the lid is hingedly coupled to thewater tub at the rear end of the humidification chamber, and at leastone operable clip is provided at the front end of the humidificationchamber.
 18. A humidification chamber according to claim 1 wherein atleast one operable clip is provided in the form of a torsion clip thatis mounted to either the lid or water tub and which is configured toengage with a catch provided on either the water tub or lid,respectively.
 19. A humidification chamber according to claim 1 whereinat least one operable clip is provided that is hingedly coupled to thelid or water tub and which is configured to engage with a catch providedon either the water tub or lid, respectively.
 20. A humidificationchamber according to claim 1 further comprising a seal about theperimeter of the chamber between the lid and water tub to seal thechamber when it is in a closed position.